The ability to read the wind is what separates good shooters from great shooters. If you want to learn wind-doping from one of the best, watch this video with 2010 National High Power Champion (and U.S. Army 2010 Soldier of the Year) Sherri Gallagher. Part of the USAMU’s Pro Tips Video Series, this video covers the basics of wind reading including: Determining wind direction and speed, Bracketing Wind, Reading Mirage, and Adjusting to cross-winds using both sight/scope adjustments and hold-off methods. Correctly determining wind angle is vital, Sheri explains, because a wind at a 90-degree angle has much more of an effect on bullet lateral movement than a headwind or tailwind. Wind speed, of course, is just as important as wind angle. To calculate wind speed, Sherri recommends “Wind Bracketing”: [This] is where you take the estimate of the highest possible condition and the lowest possible condition and [then] take the average of the two.”
It is also important to understand mirage. Sheri explains that “Mirage is the reflection of light through layers of air, based off the temperature of the ground. These layers … are blown by the wind, and can be monitored through a spotting scope to detect direction and speed. You can see what appears to be waves running across the range — this is mirage.” To best evaluate mirage, you need to set your spotting scope correctly. First get the target in sharp focus, then (on most scopes), Sheri advises that you turn your adjustment knob “a quarter-turn counter-clockwise. That will make the mirage your primary focus.”
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Photo 1: Three Near-Equal-Weight 7mm Bullets with Different Shapes
TECH TIP: Bullets of the same weight (and caliber) can generate very different pressure levels due to variances in Bearing Surface Length (BSL).
Bullet 1 (L-R), the RN/FB, has a very slight taper and only reaches its full diameter (0.284″) very near the cannelure. This taper is often seen on similar bullets — it helps reduce pressures with good accuracy. The calculated BSL of Bullet 1 was ~0.324″. The BSL of Bullet 2, in the center, was ~0.430”, and Bullet 3’s was ~ 0.463″. Obviously, bullets can be visually deceiving as to BSL!
This article from the USAMU covers an important safety issue — why you should never assume that a “book” load for a particular bullet will be safe with an equal-weight bullet of different shape/design. The shape and bearing surface of the bullet will affect the pressure generated inside the barrel. This is part of the USAMU’s Handloading Hump Day series, publiches on the USAMU Facebook page.
Beginning Handloading, Part 13:
Extrapolating Beyond Your Data, or … “I Don’t Know, What I Don’t Know!”
We continue our Handloading Safety theme, focusing on not inadvertently exceeding the boundaries of known, safe data. Bullet manufacturers’ loading manuals often display three, four, or more similar-weight bullets grouped together with one set of load recipes. The manufacturer has tested these bullets and developed safe data for that group. However, seeing data in this format can tempt loaders — especially new ones — to think that ALL bullets of a given weight and caliber can interchangeably use the same load data. Actually, not so much.
The researchers ensure their data is safe with the bullet yielding the highest pressure. Thus, all others in that group should produce equal or less pressure, and they are safe using this data.
However, bullet designs include many variables such as different bearing surface lengths, hardness, and even slight variations in diameter. These can occasionally range up to 0.001″ by design. Thus, choosing untested bullets of the same weight and caliber, and using them with data not developed for them can yield excess pressures.
This is only one of the countless reasons not to begin at or very near the highest pressure loads during load development. Always begin at the starting load and look for pressure signs as one increases powder charges.
Bullet bearing surface length (BSL) is often overlooked when considering maximum safe powder charges and pressures. In photo 1 (at top), note the differences in the bullets’ appearance. All three are 7mm, and their maximum weight difference is just five grains. Yet, the traditional round nose, flat base design on the left appears to have much more BSL than the sleeker match bullets. All things being equal, based on appearance, the RN/FB bullet seems likely to reach maximum pressure with significantly less powder than the other two designs.
Bearing Surface Measurement Considerations
Some might be tempted to use a bullet ogive comparator (or two) to measure bullets’ true BSL for comparison’s sake. Unfortunately, comparators don’t typically measure maximum bullet diameter and this approach can be deceiving.
Photo 2: The Perils of Measuring Bearing Surface Length with Comparators
In Photo 2, two 7mm comparators have been installed on a dial caliper in an attempt to measure BSL. Using this approach, the BSLs differed sharply from the original [measurements]. The comparator-measured Bullet 1 BSL was 0.694” vs. 0.324” (original), Bullet 2 was 0.601” (comparator) vs. 0.430” (original), and Bullet 3 (shown in Photo 2) was 0.602” (comparator) vs. 0.463” (original). [Editor’s comment — Note the very large difference for Bullet 1, masking the fact that the true full diameter on this bullet starts very far back.]
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Don’t Be “That Guy” (The Bad Apple on the Firing Line)
By SFC Norman Anderson, USAMU Service Rifle Team Member
You know the guy, he’s still talking at the coffee jug when his preparation period begins, then his magazines aren’t loaded when the command “STAND” is given, and finally, he doesn’t know the rules when he argues with the block officer as his target comes up marked “9 and No”. Although this guy might be the highlight of the “after match” activities, he is the proverbial bad apple on the firing line. With this example fresh in your mind, let’s go over how not to be “that guy”.
While the sport of High Power shooting is a hobby for most, all are passionate about performance throughout the day. In order to achieve your maximum performance each and every day, it is essential that you conduct yourself as a professional competitor. As a competitor, you have a personal responsibility to know the course of fire as well as the rules and procedures that apply to it and to be prepared to follow them. Knowing this will not only make you a better competitor, but it will enable you to resolve situations with other targets besides your own. So what does all this mean? I’ll explain…
Know the Course of Fire
Know the course of fire. It sounds easy enough, as we all shoot plenty of matches, but it’s more than that. If you think about it, how many people in the pits, for example, do not really know what is happening on the firing line? This leads to targets being pulled early during a rapid fire string or missing a shot during a slow fire string. In cases like this, the result is the same, delays in the match and upset competitors. To avoid being “that guy,” it is imperative that you stay tuned to the events as the day progresses. When you are at the range shooting a match, be at the range shooting the match.
At any firearms competition — be sure you know (and understand) the course of fire.
Know the Rules
Now, let’s discuss rules. As you have probably heard more than once, the rulebook is your best friend. Here is why. I can virtually guarantee that most competitors know some of the rules based only on the old “this is how we do it at home” adage. The funny part of that is, the same green NRA rulebook and orange CMP rulebooks are used to govern High Power matches all over the country.*
It is vital that all shooters be familiar with the rules as they are written, not with “how they are applied at home”. This creates consistency and continuity in how matches are conducted, from local club matches to state tournaments to National Championships. Knowledge is power when it comes to scoring targets under contention, what to do in the case of a malfunction, or even how to file a protest correctly. These rules are in place for a reason and it benefits everyone to both know and operate by these rules.
Maintain Composure and Humility — Exhibit Good Sportsmanship
One aspect of competing that cannot be forgotten is bearing. As I mentioned earlier, you must be prepared for both good and bad to happen. All too often we all see “that guy” (or that “that guy’s” gear) flying off of the firing line in disgust. Remember that we all must maintain our composure and humility in all conditions, not matter what happens. After all, it’s just a game. To put it into perspective, if it were easy, attendance would be a lot higher. Sportsmanship must be displayed in an effort to keep from ruining the day for all those around you. It doesn’t cost anything to smile, and smiling never killed anyone. So turn that frown upside down and keep on marching, better days will come.
Like a Boy Scout — Always Be Prepared
Lastly, I would like to cover preparedness. Being prepared goes beyond simply having your magazines loaded and a zero on your rifle. It means approaching the firing line, knowing what you are about to do, being ready for what is going to happen (good or bad), and being ready for the results. If you approach the firing line to merely shoot 10 shots standing in your next LEG match, you are not going to be pleased with the result. You must be prepared mentally and physically, not only for the next stage, but also the next shot. By being prepared physically (equipment ready), you give yourself peace of mind which is an essential part of being prepared mentally, and by being prepared mentally, you are less likely to become distracted and are more likely to maintain focus for each and every shot.
Conclusion — Informed Competitors Make for Better Matches
The culmination of these efforts results in a shooter that knows how to be ready for success on the range, but also and perhaps more importantly, a shooter who knows what it means to be a competitor. When you have a range full of competitors who know and follow the rules and proper match procedures, the match runs smoothly, everyone shoots well, and a good time is had by all. In the end, isn’t that what it’s all about?
* After this article was originally written, the CMP separated its rules into two different Rulebooks:
The 2016 4th Edition of the CMP Competition Rules for CMP Games Rifle and Pistol Matches governs all CMP-sanctioned matches for As-Issued Military Rifle and Pistol events including Special EIC Matches that are fired with As-Issued Military Rifles or Pistols.
The 2016 20th Edition of the CMP Competition Rules for Service Rifle and Service Pistol governs sponsored and sanctioned matches for Service Rifle, Service Pistol and .22 Rimfire Pistol events, including National Trophy Rifle and Pistol Matches, Excellence-In-Competition (EIC) matches and other CMP-sanctioned competitions.
Praslick is back! He won’t be coaching the USAMU any more but he will be helping top shooters and teams reach their goals. SFC Emil Praslick III, (U.S. Army, retired) has been hired by Berger Bullets as the company’s new Sponsorship Director. In this role, Emil will work directly with Berger’s sponsored shooters and teams. Emil will also manage Berger’s match sponsorship programs and handle Berger’s gun writer connections.
Coach of Champions — Emil Praslick
Emil’s past experiences include serving as the Head Coach of the U.S. National Long Range Rifle Team and Head Coach of the USAMU for several years. Teams coached by Emil have won 33 Inter-Service Rifle Championships. On top of that, teams he coached set 18 National records and 2 World Records. Overall, in the role of coach, Praslick can be credited with the most team wins of any coach in U.S. Military history.
Emil’s unique skill set will be a great asset for Berger-sponsored shooters. For numerous years, Emil worked tirelessly to ensure his teams and shooters performed at world-class levels, maximizing their abilities. Now, he will be doing the same for Berger’s sponsored shooters:
“My passion is coaching and working with shooters, so this is an incredible opportunity for me to help develop Team Berger by providing them with the support they need to perform at the highest level,” says Emil.
“I am thrilled that Emil has joined Berger. His experience and exceptional ability, both on and off the range, are certain to be impactful,” says Berger Bullets President, Eric Stecker.
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Each Wednesday, the U.S. Army Marksmanship Unit publishes a reloading “how-to” article on the USAMU Facebook page. Recently the USAMU’s reloading gurus looked at the subject of case lubrication. Tasked with producing thousands of rounds of ammo for team members, the USAMU’s reloading staff has developed very efficient procedures for lubricating large quantities of cases. This article reveals the USAMU’s clever “big-batch” lube methods. For other hand-loading tips, visit the USAMU Facebook page next Wednesday for the next installment.
Rapid, High-Volume Case Lubrication
Today’s topic covers methods for quickly applying spray lube to cartridge cases prior to sizing. A typical order for this shop may be 25,000 rounds, so [speeding up] the lubrication process can be a real time-saver. While your ammunition lots probably aren’t this large, the efficient methods discussed here may help save a considerable amount of time over your handloading career. Our case lubrication rates range from 1500-1600 cases per hour, to 2400-2500 cases per hour, depending on caliber.
This shop uses virgin brass, whereas most home handloaders use fired brass, which necessitates some small changes at times. These will be discussed as they arise. Begin with fired brass that has been tumbled clean.
Ensure as much tumbling media as possible is removed from the brass, as when it gets into a size die, it can dent cases significantly. This is a good time to round out dents in the case mouths using a tapered tool to prevent damage from the decapping stem.
First, dump the clean cases into a large box or reloading bin. Shake the bin back and forth so that many cases are oriented with the mouths up. Next, pick up as many cases as is convenient with the mouths “up”, from natural clusters of correctly-oriented cases. With 7.62mm-size cases, this is usually 3-4, and with 5.56mm cases, this can be up to 8-10. Place the cases into the rack slots, mouth-up. Doing this in groups rather than singly saves considerable time. Once these clusters have been depleted, it will be time to re-shake the bin to orient more cases “up.”.
This photo shows a case lubrication rack made by a USAMU staffer.
Naturally, adjust the spacing to best fit the calibers you reload. We have found this size … convenient for handling through the various phases of case lubrication/transfer to progressive case feeders for processing. Note that the 1/2-inch angle does not cover much of the critical case area at the base, just forward of the extractor groove, where most re-sizing force will be exerted. As the USAMU uses virgin brass, less lubrication is required for our brass than would be needed for Full Length (FL) sizing of previously-fired brass.
NOTE: The amount applied using our rack is easily enough for our purpose. If using fired brass, be sure to adequately lube this base area to avoid having cases stick in the full-length sizing die.
Using a spray lube, coat the cases adequately, but not excessively, from all sides. Be sure to get some lube into the case mouths/necks, in order to reduce expander ball drag and case stretching/headspace changes. The spray lube this shop uses does not harm primers or powder, and does not require tumbling to remove after lubing.*
Take a close look at the photo above. The USAMU shop uses a common kitchen turntable, which allows the rack to be rotated easily. We place this in a custom-made box which prevents over-spray on to floors and walls.
Angled Box Method for Smaller Cases to be Neck-Sized
A refinement of the above method which especially speeds processing of 5.56x45mm cases is as follows. A small cardboard box which holds about 100 cases is fitted with an angled “floor” secured by tape. With the smaller 5.56mm cases, usually about 8-10 cases per handful can be picked up, already correctly-oriented, and placed into the box together. This prevents having to place them into the rack slots, saving time.
HOWEVER, note that this does not allow nearly as much lube access to the case bodies as does the rack. For our purposes — neck-sizing and setting neck tension on new brass, this works well. If using this procedure with fired brass, take steps to ensure adequate lube to prevent stuck cases.
As always, we hope this will help our fellow handloaders. Good luck, and good shooting!
*A two-part test performed here involved spraying primed cases heavily, while getting more lube into the case mouth/body than even a careless handloader would likely apply. The second part of the test involved literally spraying considerable quantities of the lube directly into the cases, drenching the primers. After a several-day wait to allow the lube to penetrate the primers, they were then fired in a test barrel. All fired normally; no unusual reports were noted. This bolstered confidence that normal amounts of the lube would not adversely affect our ammunition, and we have been pleased with the results over several years.
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Each Wednesday, the U.S. Army Marksmanship Unit (USAMU) publishes a reloading “how-to” article on the USAMU Facebook page. This week the USAMU’s reloading gurus addressed a question frequently asked by prospective handloaders: “How much neck tension is optimal, and how should I select a neck bushing size?” The USAMU offers a straight-forward answer, suggesting that hand-loaders start with a neck bushing that sizes the neck so that it is .003″ less than the loaded outside diameter with bullet in place. From there, you can experiment with more or less tension, but this is a good starting point for many popular cartridge types.
Determining Optimal Case-Neck Tension
This week, we examine determining the correct case neck tension for optimum accuracy. Our method is simple, but relies on the use of case sizing dies which accept interchangeable neck diameter bushings graduated in 0.001″ increments. (Those readers using fixed-diameter dies with expander balls aren’t forgotten, however. Methods of tailoring these dies for proper neck tension will be found below.)
In our experience across many calibers, sizing case necks 0.003″ under the loaded-case neck diameter usually yields excellent accuracy. In other words, the sized case neck expands 0.003″ when the bullet is seated.
Bushing Choice for Optimal Sizing
Over the years, we have periodically experimented with increasing neck tension to possibly improve accuracy. In testing with machine rests at 300/600 yards, accuracy often deteriorated as neck tension increased; thus, 0.003″ expansion (from sized neck to loaded neck) is where we usually start.
Using the .260 Remington as an example, our loaded cartridge case necks measure 0.292”. Simply subtract 0.003” from that, and use a bushing that sizes necks to 0.289” (after springback). There are exceptions — sometimes, brass may be a bit soft or hard. Some case necks might need, say, 0.001” more tension, but in general, this works well.
This .003″ standard of neck tension works very well for single-loaded, long range cartridges. Depending on your caliber and firearm, it MAY also work very well for magazine-fed cartridges. If this neck tension proves inadequate for your purpose, one can increase neck tension as needed while monitoring for possible accuracy changes.
Special Considerations for Coated Bullets: If you are using moly-coated bullets, this significantly reduces the “grip” of the case neck on the bullet, and you can expect to have to tighten your case necks accordingly — particularly for magazine-fed ammunition. In any event, we do not crimp rifle cartridges, and advise against it for accuracy handloads.
Tips for Using Expander Balls
Many savvy handloaders avoid the use of expander balls in high-accuracy reloading, if possible. These can stretch cases and/or disturb the concentricity of the case neck vs. case body. If using a die with an expander ball, tapering both ends of the ball and polishing it to a mirror finish can significantly reduce these effects. (Special carbide expander ball/decapping stem sets are available for this as well.)
The typical dies used with expander balls are intended to take any cases the user may find, and size them down well below the ideal “spec” to ensure any cases will give good neck tension. The necks are then expanded up to provide heavy to medium neck tension as the expander ball exits the neck. The brass is over-worked, leading to premature work-hardening, and seated-bullet concentricity may suffer. However, the cartridges produced are perfectly adequate for most handloaders. Those who seek finest accuracy generally prefer not to over-work their brass if possible.
Another Option — Custom-Honed FL Dies
There are companies which offer to convert one’s standard dies to accept neck bushings, and that gives excellent flexibility. Another, more “old-school” approach, is to have the neck of one’s FL die honed out to the desired diameter for sizing, based on one’s case neck thickness. The expander ball may then be reduced until it barely touches the case necks after sizing, or it may be eliminated entirely. However, once performed, this modification is permanent and leaves fewer options than the bushing route, if one later changes case neck thickness.
Those shooters who turn their case necks for optimum neck wall thickness uniformity, or for a tight-neck chamber, will want to take the reduced neck wall thickness into consideration. For example, when setting up a 7mm match rifle to use a standard hunting die without an expander ball, the slightly thinner necks resulted in a perfect 0.003″ reduction in the fired-neck diameter. The result was a low-cost die that fit with custom precision and yielded excellent, match accuracy!
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Can a human, with a sling, shoot as well as a mechanical rest? The answer is “yes” (at least once in a great while) IF that sling shooter can deliver a record-breaking performance. Here’s an interesting tale of man vs. machine from our archives…
The USAMU posed an interesting challenge — could one of their shooters match the performance of a mechanical rest? Who would win in this battle between man and machine? You might just be surprised. At 600 yards, with an AR-platform rifle, the results can be remarkably close, based on targets provided by the USAMU. When clamped in a test rig, a USAMU M16A2 produced a 200-18X group with handloads. The USAMU says this was “one of our better 20-shot groups at 600 yards, testing ammo from a machine rest”. Can a human do better?
Remarkably, a human soldier came very close to matching the group shot from the machine rest. The photo below shows a 20-shot group shot by a USAMU marksman with sling and iron sights, using USAMU-loaded ammunition. The score, 200-16X, was nearly the same. As you can see, the USAMU rifleman didn’t give up much to the machine rest, even at 600 yards!
In fairness, this was no ordinary human performance. The 200-16X score was a new National Record set in December, 1994. This was fired by PFC Coleman in an Interservice Match at Okeechobee, Florida. Brilliant Performance.
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There’s no denying that 3-Gun competition is growing in popularity nationwide. Using a pistol, rifle and shotgun to shoot multiple targets at varying distances is exciting and challenging. Here are some pointers for performing better on the 3-Gun range by the USAMU’s SSG Daniel Horner, a two-time winner of Crimson Trace’s Midnight 3-Gun Invitational (M3GI) match.
Competing in Night-Time Stages
“I use the same gear all year long, so when it comes time for this match (the M3GI), I just adapt the guns, so they will work for the night time,” stated Daniel Horner. “I attach the Crimson Trace lasers and lights to the guns in whatever is the easiest way possible. Last year I just screwed a rail to my shotgun with wood screws. So, people can compete with pretty much whatever they have available and make it work.” Horner also recommends using a pair of head-mounted lamps. One can illuminate your firearms’ iron sights while the other headlamp is aimed at the targets.
The U.S. Army Marksmanship Unit (USAMU) has published a series of reloading “how-to” articles on its Facebook Page. This post explains how to uniform primer pockets and remove burrs in flash holes. These brass prep operations can help ensure greater consistency, shot after shot. Visit the USAMU Facebook Page each Wednesday for other, helpful “Handloading Hump-Day” tips.
Primer Pocket and Flash-Hole Conditioning
This week, we’ll address a question that frequently arises: “Do you uniform primer pockets and deburr flash-holes?”
As we tailor our handloading methods to the specific needs of each instance, the answer, not surprisingly, is “occasionally!” Generally, the USAMU Handloading Shop does not uniform primer pockets (PP) or deburr flash holes (FH) of our rifle brass. That’s not to say we’re against it — rather, it reflects the very high volume of ammunition loaded, the fact that very few cases are ever re-loaded for a second firing, and the types of brass we use. However, as a need is perceived, we DO deburr flash holes (of which, more later.)
As to the type cases we use, many thousands of our long-range 5.56x45mm cases come to us from the arsenal with the primer of our choice pre-installed and staked in per their usual practice. Obviously, we could not uniform either FHs or PPs on this live-primed brass. However, after careful sorting, inspection and preparation, we do obtain match-winning results with it. Regular readers have seen photos of some of the tiny 1000-yard test groups we’ve fired with weight-selected domestic brass which had neither Primer Pockets uniformed nor flash holes deburred.
Figure 1 shows a fired, deprimed 7.62×51 case with primer residue intact. In Figure 2, the primer pocket has been uniformed to SAAMI specs. Note the shiny finish — evidence of the metal removed to uniform and square the primer pocket.
Shooters who reload their brass several times may decide to uniform PPs and deburr FHs, especially on their “300-yard and beyond” brass. Unlike us, they will be using their cases many times, while the operations are only needed once. Also, most handloaders only process a relatively moderate amount of brass compared to our 20-thousand round lots. Having high quality Long Range (LR) brass helps. Many of the better brass manufacturers form their flash holes so that no burrs are created.
Still, it does pay to inspect even THESE manufacturer’s products, as occasional slips are inevitable. Very rarely, some of these makers will have a significant burr in, say, 1 per 1000 or 2000 cases, and it’s worth catching those. Recently, we began processing a large lot of match brass from a premier manufacturer, and were startled to find that every case had a burr in the FH — something we’d never before seen from this maker. We then broke out the FH deburring tool and went to work.
For those who do opt for these procedures, note that various tool models may have adjustable depth-stops. Pay attention to the instructions. Some flash hole deburring tools which enter the case mouth, not the primer pocket, depend on uniform case length for best results.
Does It Really Make a Difference?
It can be difficult to truly verify the contribution to accuracy of these procedures, particularly when firing from the shoulder, in conditions. Members of this staff, as individual rifle competitors, do often perform these operations on their privately-owned LR rifle brass.
One could ascribe this to the old High Power Rifle maxim that “if you think it helps, then it helps”. Another thought is to “leave no stone unturned” in the search for accuracy.
However, an extremely talented World Champion and Olympic Gold/Silver medalist commented on his own handloading (for International competition, which demands VERY fine accuracy). He noted that he did seem to see a decline in accuracy whenever he did not uniform FH’s, deburr FH’s and clean primer pockets before each reloading; however, with the wisdom of decades’ experience, he also remarked that “It could have been that I just wasn’t shooting as well that day.”
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Each Wednesday the USAMU offers tips for handloaders on the USAMU Facebook page. This article from the “Handloading Hump-Day” archives should interest pistol competitors, an any shooter who enjoys getting the best possible accuracy from their fine pistols. In this article, the USAMU’s experts share key tips that can help optimize your pistol ammo. Follow this tips to produce more consistent ammo, that can shoot higher scores.
Optimize the Taper Crimp
One often-overlooked aspect of handloading highly-accurate pistol ammunition is the amount of crimp and its effect on accuracy. Different amounts of taper crimp are used with various handloads to obtain best accuracy. The amount is based on bullet weight, powder burn rate and charge, plus other factors. It is not unusual for our Shop to vary a load’s crimp in degrees of 0.001″ and re-test for finest accuracy.
Use Consistent Brass
Brass is also important to pistol accuracy. While accurate ammunition can be loaded using brass of mixed parentage, that is not conducive to finest results, particularly at 50 yards. It is important for the serious competitor/handloader to use brass of the same headstamp and ideally one lot number, to maximize uniformity. Given the volumes of ammunition consumed by active pistol competitors, using inexpensive, mixed surplus brass for practice, particularly at the “short line” (25 yards), is understandable. However, for the “long line” (50 yards), purchasing and segregating a lot of high-quality brass to be used strictly for slow-fire is a wise idea.
Importance of Uniform COAL
Uniformity of the Case Overall Length (COAL) as it comes from the factory is also important to achieving utmost accuracy. More uniform case lengths (best measured after sizing) contribute to greater consistency of crimp, neck tension, ignition/burn of powder charge, and so on. Cartridge case-length consistency varies from lot to lot, as well as by maker. Some manufacturers are more consistent in this dimension than others. [Editor’s note: It is easy to trim pistol brass to uniform length. Doing this will make your taper crimps much more consistent.]
Primers and Powders — Comparison Test for Accuracy
Pay attention to primer brands, powder types and charges. Evaluating accuracy with a Ransom or other machine rest at 50 yards can quickly reveal the effect of changes made to handload recipes.
Bullet Selection — FMJ vs. JHP
Bullets are another vital issue. First, there is the question of FMJ vs. JHP. A friend of this writer spent decades making and accuracy-testing rifle and pistol bullets during QC for a major bullet manufacturer. In his experience, making highly-accurate FMJ bullets is much more difficult than making highly-accurate JHPs, in large part due to the way the jackets are formed. Small die changes could affect accuracy of FMJ lots dramatically.
The CMP now allows “safe, jacketed ammunition” in Excellence-in-Competition (EIC) Service Pistol matches, although wadcutter ammunition is prohibited. Thus, the option to use very accurate JHP designs simplifies the life of CMP Service Pistol shooters in pursuit of the prestigious Distinguished Pistol Shot badge.
Hopefully, these tips will be helpful to any pistol shooters interested in accurate handloads, not just “Bullseye” shooters. Small tweaks to one’s normal routine can pay big dividends in improved accuracy and make practice and competition more rewarding.
Stay safe, and good shooting!
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The USAMU recently published a “how-to” article about bullet sorting. While many of us may sort bullets by base-to-ogive length (and/or weight), the USAMU story explores the “how and why” of sorting bullets by Overall Length (OAL). Read the article highlights below, and make your own decision as to whether OAL sorting is worth the time and effort. Bryan Litz of Applied Ballistics says that sorting by OAL is not a bad idea, but base-to-ogive bullet sorting probably represents a better investment of your time.
Bullet Sorting by Overall Length
We’d like to share a specialized handloading technique which we’ve long found beneficial to our long-range (600 yards and beyond) accuracy. Sorting of bullets for extreme long range (LR) accuracy is not difficult to do, but some background in theory is needed.
Here at USAMU’s Handloading Shop, we only sort individual bullets for the most demanding Long-Range applications and important competitions. Only the most accurate rifles and shooters can fully exploit the benefits of this technique. The basic sorting process involves measuring the Overall Length (OAL) of the bullets, and grouping them in 0.001″ increments. It’s not unusual to find lots of match bullets that vary as much as 0.015″-0.020″ in length throughout the lot, although lots with much less variation are seen as well. Even in bullet lots with 0.015″ OAL variation, the bullet base-to-ogive length will show much less variation. Hence, our basic sort is by bullet OAL. One obvious benefit of sorting is easily seen in the attached photo. The few bullets that are VERY different from the average are culled out, reducing probable fliers.
How does one know what OAL increments to use when sorting? The answer is simple. As each lot of bullets is unique in its OAL distribution, it’s best to sample your bullet lot and see how they are distributed. In the attached photo, you will see a set of loading trays with a strip of masking tape running along the bottom. Each vertical row of holes is numbered in 0.001″ increments corresponding to the bullets’ OAL. A digital caliper makes this task much easier. As each bullet is measured, it is placed in the line of holes for its’ OAL, and gradually, a roughly bell-shaped curve begins to form.
Note that near the center, bullets are much more plentiful than near the edges. At the extreme edges, there are a few that differ markedly from the average, and these make great chronograph or sighting-in fodder. We recommend using a sample of 200 bullets from your lot, and 300 is even better. Some bullet lots are very consistent, with a tall, narrow band of highly-uniform bullets clustered together over just a few thousandths spread. Other lots will show a long, relatively flat curve (less uniform), and you may also see curves with 2 or more “spikes” separated by several 0.001″ OAL increments.
Bullet Sorting (OAL vs. Base-to-Ogive vs. Weight) — Litz Talks
I’m often asked what is a the best measure to sort bullets by, and the answer (to this and many other questions in ballistics) is: it depends.
Choosing to sort by overall length (OAL), base to ogive (BTO), bearing surface, weight, etc. can get overwhelming. Shooters typically look for something they can measure, which shows a variation and sort by that. It’s common for dimensional variations to correlate. For example, bullets which are longer in OAL are typically also shorter in BTO, and have longer noses. All these are symptoms of a bullet that was pushed a little further into the pointing die, or possibly had more than average lube while being swaged. So in essence, if you sort by BTO, you’re measuring one symptom which can indicate a pattern in the bullets shape.
So, the question still stands — what should you measure? You’ll always see more variation in OAL than BTO, so it’s easier to sort by OAL. But sometimes the bullet tips can be jagged and have small burrs which can be misleading. Measuring BTO will result in a lower spread, but is a more direct measure of bullet uniformity.
Then there’s the question of; how much variation is too much, or, how many bins should you sort into? Shooters who see 0.025” variation in BTO may choose to sort into 5 bins of 0.005”. But if you have only 0.005” variation in the box, you’ll still sort into 5 bins of 0.001”. What’s correct? You have to shoot to know. Live fire testing will answer more questions, and answer them more decisively than any amount of discussion on the subject. The test I recommend is to identify bullets on the extreme short end of the spectrum, and some on the extreme long end. Load at least 10 rounds of each, and take turns shooting 5-shot groups with them. If there is a difference, it will be evident. The results of the testing will answer your question of: should I sort based on X, Y, or Z?”
You can read more discussion on this and other similar subjects in the new Ballistics & Bullets board in the Accurateshooter.com forum. Heres a link to the thread which is discussing bullet sorting: Bullet Sorting Thread
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Each Wednesday, the U.S. Army Marksmanship Unit publishes a reloading “how-to” article on the USAMU Facebook page. On older “Handloading Hump Day” post covers removal of military primer pocket crimps. If you ever use surplus military brass, you really should this article. It contains vital information “learned the hard way”. The writer has tried many different options for removing/swaging out crimps. He weighs the pros and cons of various methods and provides some advice that will save you time and headaches. Visit the USAMU Facebook page next Wednesday for more informative articles for handloaders.
A common question, and important issue with US GI surplus 5.56 brass is “what to do with the primer crimp?” Our Handloading Shop does not prime/re-prime GI 5.56 brass, as we receive it in virgin state (primed) and don’t reload it. However, our staff has extensive private experience handloading GI brass in our own competitive shooting careers, and have several tips to offer.
Once the brass is full-length sized and decapped, the staked-in ring of displaced metal from the primer crimp remains, and hinders re-priming. Some swaging tools exist to swage out this ring, allowing free access to the primer pocket. Some are stand-alone products, and some are reloading-press mounted. Early in this writer’s High Power career, he used the common press-mounted kit several times, with less than stellar results.
Setting Up Swaging Tools
Surplus brass tends to come from mixed lots, and primer crimp varies from very mild to strong. Also, primer pocket dimensions vary. So, setting up this “one size fits most” tool involves trying to find a happy medium for a selection of different types of brass in your particular lot. Some are over-swaged, some under-swaged, and some are “Just Right.” Overall, it was a time-consuming and sub-optimal process, in this writer’s experience.
Cutting Out the Crimp Ring with a Chamfer Tool
[After trying swaging tools] this writer evolved to using the ubiquitous Wilson/RCBS/Other brands chamfer and deburring tool to cut out only the displaced crimp ring at the top of the primer pocket. One caution: DON’T OVER-DO IT! Just a little practice will let the handloader develop a “feel” for the right degree of chamfer that permits easy re-priming without removing so much metal that primer edges start to flow under pressure. For this writer, it was three half-turns of the tool in the primer pocket, with medium pressure.
Here, as with all bulk reloading operations, mechanization is our friend. A popular reloading supply house has developed an inexpensive adaptor that houses the chamfer/deburr tool (retained by an allen screw) and allows mounting in a hand drill or drill press. This speeds the operation significantly, as does use of one of the popular Case Preparation Stations that feature multiple powered operations. (Say good-bye to carpal tunnel syndrome and arthritis!)
One advantage of chamfering the primer pockets lightly to remove remnants of primer crimp, vs. swaging, is that primer pockets are not loosened in this process. US GI (usually LC) NATO 5.56 brass has a great reputation for longevity due to the superior hardness of the case head vs. some softer brands of commercial brass. This means the brass will stand up well to multiple full-pressure loads without loosening primer pockets, and the chamfering method helps support this benefit.
Powered Case Prep Centers — What to Look For
A word of advice (often learned the hard way) — think carefully before jumping on the “latest/greatest” case prep center. One with a proven, long-time track record of durability and excellent customer support has a lot going for it, vs. the flashy “new kid on the block.” Analyze the functions each case prep center can support simultaneously — i.e., can it chamfer, deburr and clean primer pockets all at the same time, without having to re-configure?
Do the tool-heads that come with it look truly functional and durable? If not, can they be easily replaced with proven or more-needed versions, such as a VLD chamfer tool, or a solid/textured primer pocket cleaner rather than a less-durable wire-brush type?
Tips for Priming with Progressive Presses
When re-priming, a couple of factors are worth noting. When re-priming using either single-stage presses, hand tools, or bench-mounted tools (such as the RCBS bench-mounted priming tool), precise alignment of the primer pocket entrance with the primer is easily achieved, and priming goes very smoothly. When using certain progressive presses, due to the tolerances involved in shell-heads, etc., one may occasionally encounter a primer that isn’t quite perfectly aligned with the primer pocket.
If resistance is felt when attempting to re-prime, DO NOT attempt to force the primer in — doing so can be dangerous! Rather, just exert SLIGHT upward pressure to keep the primer in contact with the case-head, and with the support hand, move the case back/forth a trifle. The primer will drop into alignment with the primer pocket, and then prime as usual. After priming, check each seated primer by feel. Ensure it is below flush with the case head (cleaning primer pockets helps here), and that there are no snags, burrs or deformed primers.
More Info on Primer Pocket Swaging
For more information about removing military crimps in primer pockets, we recommend you read Get the Crimp Out on the Squibloads Gun Thoughts Blog. This is a detailed, well-illustrated article that shows how to use various primer pocket reamers/cutters. It also has a very extensive discussion of swaging using CH4D, RCBS, and Dillon tools. The Squibloads author had much better luck with swaging tools than did the USAMU’s writer — so if you are considering swaging, definitely read the Squibloads article.
The illustration of primer pocket types is from the Squibloads Blog Article, Get the Crimp Out.
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To succeed in long-range shooting matches, given the high level of competition these days, you’ll need solid wind-reading abilities. We’ve found an article by SFC Emil Praslick III, retired USAMU Service Rifle coach and U.S. Palma Team Coach, that can help you make better wind calls in competition.
Emil Praslick, now retired from the U.S. Army, is considered one of the best wind gurus in the United States, if not the world. During his service with the USAMU he authored an excellent two-part article on wind reading that is available on the CMP (Civilian Marksmanship Program) website. Both articles contain helpful illustrations, and are “must-read” resources for any long-range shooter–not just Service Rifle and Highpower competitors.
Part One covers basic principles, tactics, and strategies, with a focus on the 200-yard stages. Emil writes: “There are as many dimensions to ‘wind reading’ as there are stages to High Power competition. Your tactical mindset, or philosophy, must be different for the 200 and 300 yard rapid-fire stages than it would be for the 600 yard slow-fire. In the slow-fire stages you have the ability to adjust windage from shot to shot, utilizing the location of the previous shot as an indicator. Additionally, a change to the existing conditions can be identified and adjusted for prior to shooting the next shot.”
In Part Two, Praslick provides more detailed explanations of the key principles of wind zeros, wind reading, and the “Clock System” for determining wind values: “The Value of the wind is as important as its speed when deciding the proper windage to place on the rifle. A 10 MPH wind from ’12 o-clock’ has No Value, hence it will not effect the flight of the bullet. A 10 MPH wind from ‘3 o’clock’, however, would be classified as Full Value. Failure to correct for a Full Value wind will surely result in a less than desirable result.”
Praslick also explains how to identify and evaluate mirage:
Determine the accuracy of the mirage. Mirage is the reflection of light through layers of air that have different temperatures than the ground. These layers are blown by the wind and can be monitored to detect wind direction and speed.
Focus your scope midway between yourself and the target, this will make mirage appear more prominent. I must emphasize the importance of experience when using mirage as a wind-reading tool. The best way to become proficient in the use of mirage is to correlate its appearance to a known condition. Using this as a baseline, changes in mirage can be equated to changes in the value of the wind. Above all, you must practice this skill!
Click HERE for more excellent instructional articles by Emil Praslick and other USAMU Coaches and shooters.
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If you shoot a pistol, you should watch this video. It covers the key fundamentals of handgun shooting: stance, arm position, grip, sight alignment, and trigger control. This excellent video features USAMU shooter SGT Shane Coley.
Arm/Elbow Position: You should not lock your elbows says SGT Coley: “Because my elbows are slightly bent, it allows the recoil to transfer into my shoulders, down my core, into my legs and to the ground, allowing me to maintain a flat-shooting gun … on multiple targets.”
Grip (Hand Position): SGT Coley explains how to divide the support between both hands: “In terms of grip pressure, I’m applying about 60% to my support hand, and 40% to my strong hand. This is because I need to maintain dexterity with my strong hand to operate the trigger at high rates of speed.”
Trigger Control: The placement of your finger on the trigger blade itself is very important notes Coley: “Putting too much (or not enough) of your finger on the trigger can cause you to pull or push your shots. When you squeeze the trigger, make sure to squeeze it all the way to the rear, in one smooth motion. A quick dry-fire drill to help you with this is to take an empty piece of brass and place it on the front of your slide. Aim at the target, and with the proper trigger control, you should be able to break the shot without the piece of brass falling.”
On the web, you’ll find hundreds of pistol shooting videos — some good, some not helpful at all. In some of those “not helpful” videos the featured shooter has bad habits, or more often than not, he exhibits poor accuracy on target. You won’t find those kinds of shortcomings in this USAMU-sponsored video. SGT Coley doesn’t make foolish mistakes, nor does he exhibit bad habits when shooting. And his accuracy is outstanding. When you look for a pistol trainer — stick to someone like SGT Coley, who has solid fundamentals, the complete skill set, and superior accuracy. A trainer can’t teach a skill that he doesn’t understand himself.
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Top to bottom – Remington firing pin assembly with ISS, Tubb SpeedLock alloy-composite system without ISS (current versions have dual, opposite-wound springs), and Remington short action firing pin assembly without ISS.
Each Wednesday, the U.S. Army Marksmanship Unit publishes a reloading “how-to” article on the USAMU Facebook page. Last week’s “Handloading Hump Day” article covered mechanical issues and related ignition irregularities that can cause vertical fliers even with good ammunition in an otherwise excellent rifle. We highly recommend you read this article, which offers some important tech tips.
Vertical Dispersion: Mechanical/Ignition Issues?
Poor or inconsistent ignition has long been known to be one of the “usual suspects” when one encounters vertical fliers that just shouldn’t be there. By having a sense of some of the basic principles involved, and a few basic areas to check, the shooter may avoid colsiderable frustration, not to mention time, expensive loading components and barrel wear.
Is your well-built rifle of high-quality components plagued with vertical fliers across more than 1-3 handload combinations? Consider the bedding, crown and scope/sight mounts. Are they correct? If so, then you might check for ignition issues before boldly undertaking an extensive, expensive, and quite possibly fruitless quest for the “magic handload”.
SEEING IS BELIEVING: While the author had been aware for many years that poor ignition should be considered and ruled out when dealing with vertical fliers in an otherwise-excellent rifle, actually seeing the problem and its almost instantaneous cure really drove the lesson home.
He was working with a “dot” rifle – a .22 LR match rifle that really stacked bullets into little piles at 50 yards and beyond. With one lot of ELEY Tenex, it produced consistent “bughole” groups at 50, but with another, selected lot of Tenex, similar groups were regularly ruined by single, vertical fliers that did not appear in other rifles. Rather than spending days burning up expensive, select ammunition looking for “magic lots”, he contacted a well-respected rimfire gunsmith and explained the situation.
Without so much as batting an eye, the highly-experienced ‘smith tore into the rifle’s action, and quickly found the cause(s) of the problem. He discovered a demonstrably weak firing pin spring, plus a chip out of the face of the firing pin where it contacted the cartridge rim.
After replacing and tuning the offending parts, the rifle immediately began shooting tiny, bughole groups with the previously “unacceptable” lot of Tenex. Centerfire rifles can also benefit from ensuring positive, consistent ignition. A wise riflesmith is literally worth his weight in gold!
So, what are some issues we as shooters can inspect in our rifles to help determine if ignition woes could be part of our problem? At the club level, ask yourself if that “experienced” Remington, Winchester 70, or even Springfield-based match bolt gun you’re using is still running its’ original 40-80 year-old factory striker spring? If so, a new replacement is cheap insurance against current or future problems. (And BTW, it might be best to stick to the normal, factory-spec spring weight. A super-powerful spring can cause vertical, just as a weak one one can.) Along with that, a routine check for proper firing-pin protrusion is a quick preventive measure that can rule out potential issues.
Other areas to consider are the centering and consistency of the firing pin’s operation in the bolt. Admittedly, with the increasing use of precision-machined custom actions, this is becoming less an issue every day. Below is the firing pin assembly from a custom BAT action:
However, particularly with factory actions, a very quick and easy check is to remove the bolt, let the firing pin go forward, and look at the firing pin tip through the firing pin hole. Is the tip off-center in the hole, and possibly striking it as it moves forward? Is the hole out-of-round or burred from being struck repeatedly? If so, a trip to the riflesmith is likely in order.
Similarly, machining issues in the bolt/firing pin system can lead to rough and erratic firing pin movement, in which the firing pin drags against an internal surface of the bolt. In high-quality rifles these issues are relatively rare, but not unheard-of, and it takes mere minutes to rule them out. It may be worthwhile to remove the cocking piece/firing pin/spring assembly and look for any unusual gouges, dings, peening, burrs or signs of abnormal wear.
This task is especially easy with Winchester 70s, Springfields, and the similar Mauser 98s, involving little more than the push of a button and unscrewing the cocking piece assembly. This is just one of the many reasons these tried-and-true actions have earned such a loyal following in the field, among hunters who must maintain their rifles away from a shop.
Particularly with older rifles, watch for and remove excess grease (or even Cosmoline!) from both the firing pin assembly and inside the bolt. This can help improve firing pin speed and consistency. Other bolt-action designs may need a take-down tool or other measures.
As part of this inspection, AFTER ENSURING THE RIFLE IS UNLOADED, slowly cock the rifle, dry-fire, and repeat several times. Listen carefully near the action for inconsistency in the sounds it generates. Does the striker falling make the same sound each time? Do you hear or feel grinding upon operation? If so, where?
Be sure to check the operation of the cocking piece (bolt shroud), firing pin within the bolt shroud, the cocking piece cam and the rear of the bolt body where the cocking piece cam operates. As with our examination for abnormal wear marks discussed above, look for marks indicating roughness or a possible need for light polishing. Then, clean and lightly grease the bearing surfaces while you’re at it.
Remington 700 bolt shroud and cocking cam
These are relatively easy checks that shooters can undertake to perform a preliminary inspection on their own. Other mechanical issues can also cause ignition issues, chiefly centered around the action of the trigger, sear and sear spring. If these are suspected, a trip to an experienced, qualified riflesmith for diagnosis is recommended. We hope you find this information helpful! Join us again next week, and in the meantime, enjoy the shooting sports safely!
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SFC Emil Praslick III is now retired from the U.S. Army, but he left a great legacy as one of the USAMU’s greatest coaches and team leaders. A highly-respected wind expert, Praslick also was known for his ability to help his shooters master the “mental game”, which is so important at the highest levels of competition. Here is an article from the CMP Archives in which Praslick explains how to focus your mind to achieve greater success.
Thinking Your Way to Success by SFC Emil Praslick III (Ret.)
Why does it seem that the same small group of shooters wins the majority of the matches? Within the Army Marksmanship Unit’s Service Rifle Team, the same effect applies. On a team filled with uncommonly talented shooters, the same two or three are consistently at the top of the final results bulletin. What is the difference among shooters who are technically equal? Confidence. A confident shooter is free to execute his shots without the fear of failure, i.e. shooting a poor shot.
Negative thoughts (can’t, won’t be able to, etc.) will destroy a skilled performance. The mind’s focus will not be on executing the task, but on projecting fear and self-doubt. Fear is the enemy, confidence is the cure.
How does a shooter on the eve of an important match (the President’s or NTI, for example) attain the confidence needed to perform up to his potential? A pre-competition mental plan can assist in acquiring that positive mental state. The plan can be broken down into a few phases.
Build a feeling of preparedness. Developing and executing a plan to organize your equipment and pre-match routine will aid you in feeling prepared on match day.
Avoid negative and stressful thoughts. Focusing on “winning” the match or shooting for a specific score (like making the “cut” or making the President’s 100) can cause undue stress. Good shooters focus on aspects that are within their control: their sight picture, their sight alignment, their position. Each shot should be treated as an individual event.
Train stage-specific tasks during your practice sessions. Instead of shooting matches or practice matches only, include some drills that focus on your problem areas. Training in this manner will assist your level of confidence.
As part of your pre-match routine, imagine yourself shooting perfect shots. Visualize getting into the perfect position, acquiring a perfect sight picture, and perfect trigger control.
Let a feeling of calm and well-being wash over you. Spend a few minutes alone thinking positive thoughts. Many shooters use their favorite music to help build the mood.
Once you develop your pre-competition mental plan, stick with it. Through your training you will develop the physical skills to shoot higher scores. The confidence you will need to apply them in match conditions will grow as you develop into a complete shooter; both physically and mentally.
The USAMU’s article archives are a great resource for competitive shooters. Click HERE for more excellent instructional articles by Emil Praslick and other USAMU Coaches and shooters. You’ll find articles on Wind-Reading, Fitness, Equipment, Shooting Positions, Shooting Techniques, Match Strategies and much more.
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One of our Forum members asked: “Are there any good books on pistol marksmanship? I’m looking for a book that covers techniques and concepts….” Here are our recommendations — six titles that can make you a better pistol shooter. These books run the gamut from basic handgun training to Olympic-level bullseye shooting.
Good Guidebooks for Pistol Shooters
There are actually many good books which can help both novice and experienced pistol shooters improve their skills and accuracy. For new pistol shooters, we recommend the NRA Guide to the Basics of Pistol Shooting. This full-color publication is the designated student “textbook” for the NRA Basic Pistol Shooting Course.
Serious competitive pistol shooters should definitely read Pistol Shooters Treasury a compilation of articles from World and National Champions published by Gil Hebard. You could work your way through the ranks with that book alone even though it is very small. It is an excellent resource.
If you’re interested in bullseye shooting, you should get the USAMU’s The Advanced Pistol Marksmanship Manual. This USAMU pistol marksmanship guide has been a trusted resource since the 1960s. Action Shooters should read Practical Shooting: Beyond Fundamentals by Brian Enos, and Ben Stoeger’s new-for-2013 Practical Pistol Book. Brian Enos is a well-known pistol competitor with many titles. Ben Stoeger is a two-time U.S. Practical Pistol shooting champion and a member of the USA Team at the 2011 World Pistol Championships. Last but not least, Julie Golob’s new Shooting book covers pistol marksmanship, along with 3-Gun competition. Julie holds multiple national pistol shooting titles.
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Each Wednesday, the U.S. Army Marksmanship Unit publishes a reloading “how-to” article on the USAMU Facebook page. Yesterday’s post covered primer seating depth. This article offers many useful tips — including a clever way to measure primer seating depth with ordinary jaw-type calipers. Visit the USAMU Facebook page next Wednesday for the next installment.
Primer Seating Depth — Why Uniformity is Important
The first concern is for safety: for that reason, primers should be seated below flush with the case head. One primary cause of “slam fires” (which includes catastrophic failures from firing out of battery) is “high,” or protruding primers. These stand above the case head, are readily felt with simple finger-tip inspection, and may fire when slammed by the bolt face and/or a floating firing pin in feeding.
Here at the USAMU, we ensure our rifle primers generally run -0.003″ to -0.005″ below the case head. Maximum primer depth is -0.006″ and minimum is -0.002″. Upon inspection, any cases with high primers will be corrected before loading. Aside from improving ballistic uniformity, ensuring the primers have proper compression upon seating also helps reduce possible misfires. These can be caused by the firing pin’s expending part of its energy either seating the primer or having to deform the primer cup enough to reach the anvil.
SMART TIP: How to Measure Primer Seating Depth with a Set of Calipers
A zeroed, precision set of standard calipers will also measure primer seating depth. (You don’t really need a custom tool.) Merely close the jaws and place the calipers’ narrow end squarely across the center of the case head/primer pocket. Keeping the narrow end in full contact with the case head, gently open the jaws, and the center bar will extend until it reaches the primer face. Voilà! Primer depth is read on the dial. Taking a few measurements to ensure accuracy and repeatability is recommended until one is familiar with this technique.
Brass and Primer Defects Can Cause Seating-Depth Variances
Factors affecting variance of primer seating depth include brass maker and lot number — all primer pockets are not created equal! Another factor is the primer manufacturer and individual primer lot. We’ve encountered occasional primer lots by top-quality makers that included some primers with slight defects affecting seating. While finely accurate, these primers were out-of-round or had small slivers of cup material protruding which affected primer feeding or seating depth.
Has one’s brass been fired previously? If so, how many times and the pressures involved also affect future primer seating. Obviously, this is another factor in favor of segregating one’s high-accuracy brass by maker, lot number, and number of times fired, if possible.
Measuring Primer Seating Depth with Purpose-Built Gauge
The next question, “How do we measure primer depth?” happily can be answered using tools already owned by most handloaders. [See tip above on how to measure depth with calipers.] At the USAMU, we have the luxury of purpose-built gauges made by the talented machinists of the Custom Firearms Shop. One places the primed case into the gauge, and the dial indicator reads the depth quickly and easily. The indicator is calibrated using a squarely-machined plug that simulates a case head with a perfectly flush-seated primer, easily giving meaningful “minus” or “plus” readings. The gauge is usable with a variety of case head sizes.
Primer Seating with Progressive Presses
Methods of primer seating include hand-seating using either hand held or bench-mounted tools, vs. progressive-press seating. Progressive presses may either seat by “feel,” subjective to each operator, or by using a mechanical “stop” that positively locates primers nearly identically every time. Testing here has shown that we get more uniform seating with the latter type progressive press, than we do with a high-quality bench-mounted tool lacking a positive stop.
Primer stop depth adjustments on our main progressive presses involve turning a punch screw in and out. While the screw is not calibrated, fine “tick” marks added to the top of the press help users gauge/repeat settings by “eye” efficiently with practice. Then, once a sample of primed cases is run to confirm the range and accuracy of depths, the identifying lot number and maker is noted on the press for reference. When it’s necessary to switch brass/primer lots, changes are easy to make and settings are easily repeated when it’s time to switch back.
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Each Wednesday, the U.S. Army Marksmanship Unit publishes a reloading “how-to” article on the USAMU Facebook page. This past week’s “Handloading Hump Day” article, the latest in a 7-part series, relates to chronograph testing and statistical samples. We highly recommend you read this article, which offers some important tips that can benefit any hand-loader. Visit the USAMU Facebook page next Wednesday for the next installment.
Chronograph Testing — Set-Up, Sample Sizes, and Velocity Factors
Initial Chronograph Setup
A chronograph is an instrument designed to measure bullet velocity. Typically, the bullet casts a shadow as it passes over two electronic sensors placed a given distance apart. The first screen is the “start” screen, and it triggers an internal, high-speed counter. As the bullet passes the second, or “stop” screen, the counter is stopped. Then, appropriate math of time vs. distance traveled reveals the bullet’s velocity. Most home chronographs use either 2- or 4-foot spacing between sensors. Longer spacing can add some accuracy to the system, but with high-quality chronographs, 4-foot spacing is certainly adequate.
Laboratory chronographs usually have six feet or more between sensors. Depending upon the make and model of ones chronograph, it should come with instructions on how far the “start” screen should be placed from one’s muzzle. Other details include adequate light (indoors or outdoors), light diffusers over the sensors as needed, and protecting the start screen from blast and debris such as shotgun wads, etc. When assembling a sky-screen system, the spacing between sensors must be extremely accurate to allow correct velocity readings.
Statistics: Group Sizes, Distances and Sample Sizes
How many groups should we fire, and how many shots per group? These questions are matters of judgment, to a degree. First, to best assess how ones ammunition will perform in competition, it should be test-fired at the actual distance for which it will be used. [That means] 600-yard or 1000-yard ammo should be tested at 600 and 1000 yards, respectively, if possible. It is possible to work up very accurate ammunition at 100 or 200 yards that does not perform well as ranges increase. Sometimes, a change in powder type can correct this and produce a load that really shines at longer range.
The number of shots fired per group should be realistic for the course of fire. That is, if one will be firing 10-shot strings in competition then final accuracy testing, at least, should involve 10-shot strings. These will reflect the rifles’ true capability. Knowing this will help the shooter better decide in competition whether a shot requires a sight adjustment, or if it merely struck within the normal accuracy radius of his rifle.
How many groups are needed for a valid test? Here, much depends on the precision with which one can gather the accuracy data. If shooting from a machine rest in good weather conditions, two or three 10-shot groups at full distance may be very adequate. If it’s windy, the rifle or ammunition are marginal, or the shooter is not confident in his ability to consistently fire every shot accurately, then a few more groups may give a better picture of the rifle’s true average.
Preliminary Load Development and Velocities
When developing a load for ones firearm, a chronograph is a very useful tool. Naturally, it tells the bullet speed, allowing ballistic calculations for wind deflection and trajectory, as well as velocity variation. It can also be used, in conjunction with recent handloading manuals, as an indirect indicator of pressure.
Differences between individual barrels, chamber throats, and powder lots, plus many other variables, can cause results to differ from those cited in the manuals. Thus, beware the notion of a “magical high-speed barrel.”
When Velocities Raise Pressure Concerns — Suppose the manual states that their 26-inch .260 barrel achieved 2900 fps with X bullet, Y powder, Z case, and W primer. If you achieve that speed with identical components in your 26-inch barrel while using five (5) grains less powder, that should raise a red flag. Pressures may be at or near maximum in your rifle, despite the higher “maximum” charge cited in the manual. Observe for pressure indicators as discussed in your manuals, and never exceed published maximum powder charges.
When working up a potential match load for your rifle, it is wise to survey at least 2-3 current factory sources of data for your powder/bullet combination. This will give you a sense of the variations possible due to random factors. Then, beginning at a safe, listed “starting” powder charge, work your way up in increasing powder increments while shooting over the chronograph. Also, assess your brass and rifle for signs of increasing pressure.
What size powder increments should be used? This depends on the case volume and powder chosen. A 0.3 grain or 0.5 grain increase in powder charge may be significant in a .223, but of little consequence in a .300 Magnum. Faster burning powders are more sensitive to small changes in powder charge, increasing pressures more rapidly than slow-burning powders.
Chronograph Sample Sizes — Factors to Consider
How many shots should one fire to obtain an accurate velocity for each powder charge increment when loading? That depends in part on the uniformity of velocities given by your particular powder/bullet/barrel combination.
For example: a 3- or 5-shot sample gives an extreme spread (ES) of 140 fps between the high and low velocities recorded. The lack of uniformity indicates that firing 1 or 2 shots over the chronograph to check a powder charge is likely to give a wide margin of error. In such a case, larger sample sizes will give a better idea of the true, average velocity. While approaching the loading manual’s listed maximum charge, track the ascending velocities per charge increment. One may well see that as charges approach maximum, velocities may become much more uniform. Moreover, velocity gains per increment of increase often become smaller. Ideally, one won’t encounter velocity variations this large. Changing primers and/or neck tension may increase uniformity. If wide variations persist, however, a different powder may offer great improvement.
Consider this: A 2-shot scan gives double the data of a one-shot sample. A 4-shot sample gives twice the data of a 2-shot scan. Larger samples are particularly useful if there is much velocity variation in the population.
On the other hand, one might already be familiar with a particular powder/bullet combination in one’s barrel. If it is known to have little variation, a 1 or 2-shot scan in the early stages while working up toward the maximum can be useful, while saving expensive bullets. As powder charges approach their maximum, some like to test accuracy while shooting over the chronograph. Although it’s a bit trickier to set up the bench, chronograph and target, this does yield more data per bullets expended. In such an instance, 5-shot or even 10-shot groups may be desirable at times.
Consider 20-Shot Sample for Long-Range Match Loads
Once one arrives at a load combination intended for competition use, one should chronograph at least a 10-shot sample. This gives a reasonable picture both of the load’s uniformity and its average velocity. For long range use, a 20-shot sample of ones finalized match load is even better. This accurately shows the uniformity of one’s velocities over time. It is more likely to reveal any rare shots that develop velocities significantly different from the average.
Thus ends Part 7 in our series on Accuracy Testing and Chronographing. Next week, we’ll conclude our section on Chronograph Testing. Until then, stay safe and enjoy the shooting sports!
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SFC Michael McPhail, shown above, is currently ranked #1 in the world in the smallbore 50m prone rifle discipline. He’s one of the favorites to win Gold in 2016.
As the 2015 international shooting season comes to a close, the USAMU shooting teams are preparing for the 2016 Olympic trials and a chance to compete in the Olympic Games in Rio de Janeiro next summer. One USAMU marksman who has already secured a berth for the 2016 Olympics is SFC Michael McPhail of Darlington, Wisconsin.
SFC Michael McPhail, ranked number one in the world in men’s 50-meter rifle prone, already won his spot on the U.S. Olympic team by virtue of his performances in 2015 ISSF World Cup events. McPhail, of Darlington, Wisconsin, won the ISSF World Cup Finals in Munich this September. McPhail also won back-to-back gold medals at the ISSF World Cup events at Fort Benning, GA and Munich, Germany, held in May and early June of 2015.
Michael McPhail Secures Olympic Team Nomination with World Cup Finals Triumph
McPhail said for anyone who wants to participate in the Olympics, the Army provides superior coaching, training, equipment and ammunition. “For a kid who shoots and their goal is to make the Olympics, the Army Marksmanship Unit is the place to go,” McPhail said.
SFC Jason Parker, International Rifle and Pistol Teams coach noted that: “Sergeant First Class McPhail has had a fantastic year. He has a great potential for medaling in the Olympic Games.”
With one seat already taken by McPhail for men’s 50-meter rifle prone, two other USAMU Soldiers are Parker’s top picks for the second and final seat. They are SFC Eric Uptagrafft and SSG George Norton. “Sergeant First Class Uptagrafft is another top contender for making the United States Olympic Team,” Parker said. “In the past, he has won multiple world class medals, he has been to two Olympics already, and he is one of our top shooters. He will be trying to get that last spot in the prone, and I wouldn’t count him out of anything.”
For more information on the U.S. Army Marksmanship Unit, visit www.USAMU.com.
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