When you make a reloading mistake, you may need to “pull down” assembled ammo. The embedded UltimateReloader.com video demonstrates how to use the Hornady Cam-Lock bullet pulling system.
When Reloading Goes Bad — The Danger of Over-Charging
Our friend Gavin Gear of UltimateReloader.com was recently reloading some 9mm pistol ammo with his Hornady progressive press. As part of his reloading procedure, he visually checks the cases — and he noticed that the charges seemed high. Sure enough, his most recently-produced rounds were about two grains over spec. He diagnosed the issue: “I was using a powder measure without a baffle. What happened was, over the course of the loading session, things settled in, and the charge level increased.”
Not knowing just when his powder measure started delivering too much powder, Gavin decided, for safety’s sake, to pull down all the ammo he had just reloaded. Yes that’s time-consuming, but it’s better than the alternative — having a dangerous Kaboom while shooting. With fast-burning pistol powders, a two-grain over-charge could cause a blown case, damaged firearm, and/or serious injury.
Watch Cam-Lock Bullet Puller Used to Remove Bullets from Loaded Ammo:
Use of Bullet Puller starts 4:00 minutes into video.
Gavin says it is vitally important to perform safety checks during the reloading process: “You’ve got to do it — check every single round to make sure there IS powder, and that there’s not too MUCH powder. Double, Triple, Quadruple check your components… and your powder charges. You can’t be too careful.”
To pull down a loaded round, first place the cartridge in the shellholder on your press ram. Then raise the round up into the bullet puller device installed where a die would go. The Hornady Cam-lock bullet puller works by clamping the bullet in a collet when you flip down the red-coated lever. Then, with the case held by the rim in the shell-holder, the bullet exits the cartridge as the press ram is lowered. It takes time, but it’s pretty fool-proof once you get the hang of it. This entire process is illustrated in Gavin’s video, starting near the four-minute mark.
The Hornady Cam Lock Bullet Puller has four (4) key components: 1. Cam-Lock die body; 2. Cam-Lock lever; 3. Stem; and 4. Collet (Caliber-specific).
NOTE: In order to use this tool, you’ll need the appropriate collet for each diameter range of bullets you intend to pull. For example use collet #3 for 6mm, collect #6 for 7mm, and collet #7 for .308 Caliber.
RCBS Lock-Out Die
A good safety option for users with progressive presses is the RCBS Lock-Out Die. This has a charge detection rod that dips into each case after powder has dropped. You adjust the die to the proper charge height for your desired load. If the actual dispensed charge is too high or too low, the Lock-Out Die senses the problem and stops the press from advancing to the next case (it does this by preventing the ram/shellplate from fully elevating). We’ve used the Lock-out die with success for both pistol and rifle cartridges. It’s sensitive to about one-half grain with pistol powders.
This Lock-Out Die works with Hornady and Dillon progressives as well as with RCBS progressives. It does take up one die station on the press.
The U.S. Army Marksmanship Unit regularly publishes a reloading “how-to” article on the USAMU Facebook page. One excellent “Handloading Hump Day” post covered preparation of once-fired 5.56x45mm brass. This article, the first in a 3-part series, has many useful tips. If you shoot a rifle chambered in .223 Rem or 5.56x45mm, this article is worth reading.
This week, Handloading Hump-Day will answer a special request from several competitive shooters who asked about procedures for morphing once-fired GI 5.56mm brass into accurate match brass for NRA High Power Rifle use. The USAMU has used virgin Lake City (LC) 5.56 brass to win National Championships and set National Records for many years. In this 3-part series, we’ll share techniques proven to wring match-winning accuracy from combat-grade brass.
GI brass has an excellent attribute, worth noting — it is virtually indestructible. Due to its NATO-spec hardness, the primer pockets last much longer than most commercial brass when using loads at appropriate pressures.
Preparing Once-Fired GI 5.56 Brass for Reloading (Part 1 of 3)
Assuming our readers will be getting brass once-fired as received from surplus dealers, the following steps can help process the low-cost raw material into reliably accurate components.
1. Clean the Brass
First, clean the brass of any dirt/mud/debris, if applicable. Depending on the brass’s condition, washing it in a soap solution followed by a thorough rinsing may help. [This step also extends the life of the tumbling media.] Approaches range from low-tech, using gallon jugs 1/2 full of water/dish soap plus brass and shaking vigorously, to more high-tech, expensive and time-consuming methods.
2. Wet-Tumbling Options (Be Sure to Dry the Brass)
When applying the final cleaning/polish, some use tumblers with liquid cleaning media and stainless steel pins for a brilliant shine inside and out, while others take the traditional vibratory tumbler/ground media approach. Degree of case shine is purely personal preference, but the key issue is simple cleanliness to avoid scratching ones’ dies.
If a liquid cleaner is used, be SURE to dry the cases thoroughly to preclude corrosion inside. One method is to dump the wet brass into an old pillow case, then tilt it left/right so the cases re-orient themselves while shifting from corner to corner. Several repetitions, pausing at each corner until water stops draining, will remove most water. They can then be left to air-dry on a towel, or can be dried in a warm (150° F-200° F max) oven for a few minutes to speed evaporation.
Shown below are Lake City cases after cleaning with Stainless Media (STM). Note: STM Case cleaning was done by a third party, not the USAMU, which does not endorse any particular cleaning method.
3. Inspect Every Case
Once dry, inspect each case for significant deformation (i.e., someone stepped on it), damaged mouths/necks and case head/rim damage. Some rifles’ ejectors actually dig small chunks of brass out of the case head — obviously, not ideal for precision shooting. Similarly, some extractors can bend the case rims so badly that distortion is visible when spinning them in one’s fingers. These can be used for plinking, but our match brass should have straight, undamaged rims.
Dented case mouths are common, and these can easily be rounded using a conical, tapered tool, [such as a .223 expander mandrel. A dummy 7.62 or .30-06 cartridge with a FMJ spitzer can also work.] If most of your brass is of one headstamp, this is a good time to cull out any odd cases.
4. Check the Primers Before Decapping
Your clean, dry and inspected brass is now ready for full-length sizing, decapping and re-priming. Historically, primer crimps on GI brass have caused some head-scratching (and vile language) among handloaders. Our next installment will detail efficient, easy and practical methods to remove primer crimp, plus other useful handloading tips. Until next week, Good Shooting!
NOTE: The USAMU Handloading (HL) Shop does not RE-load fired 5.56 brass. We use virgin LC brass with our chosen primer already staked in place. However, our staff has extensive personal experience reloading GI brass for competition, which will supplement the Shop’s customary steps. In handloading, as in life, there are many ways to accomplish any given task. Our suggestions are note presented as the “only way,” by any means. Time for loading/practicing is always at a premium. Readers who have more efficient, alternative methods that maintain top accuracy are invited to share them here.
Accuracy Potential of Mil-Surp 5.56×45 Brass
So, how accurate can previously-fired GI surplus brass be in a good National Match AR-15? Well, here’s a data point from many years ago that might be of interest. A High Power shooter who wrote for the late Precision Shooting magazine took a Bill Wylde-built AR match rifle to a registered Benchrest match. His first 5-round group ever fired in a BR match was officially measured at 0.231″ at 200 hundred yards. This was fired in front of witnesses, while using a moving target backer that confirmed all five rounds were fired.
He recounted that his ammo was loaded progressively with factory 52gr match bullets and a spherical powder using mixed years of LC brass with no special preparation whatsoever. Obviously, this was “exceptional”. However, he had no difficulty obtaining consistent 0.5-0.6 MOA accuracy at 200 yards using LC brass and a generic “practice” load that was not tuned to his rifle.
Saving Money by Using GI Brass
So, with good commercial brass readily available, why would one go to all the extra steps necessary to process fired GI brass? [Editor: It’s about saving money.]
Economically, it makes great sense. When the author was actively practicing and competing with the service rifle, he had ~3,000 rounds of 5.56mm brass, which allowed him to load during winter and spend most time in the summer practicing. If one were wealthy and wanted to shoot nothing but the finest imported brass, the current cost of 3,000 is ~$1920 (plus shipping.)
Dropping down to good, but less-expensive new, U.S. commercial brass brings the price to a much more realistic ~$720. However, at current rates, the same amount of surplus GI once-fired brass costs between $120 — $150, leaving lots of room in the budget for other expenses. [Editor: that’s less than 10% of the cost of the best imported brass.]
Figure 1. When the bullet is seated farther out of the case, there is more volume available for powder. This enables the cartridge to generate higher muzzle velocity with the same pressure.
Effects Of Cartridge Over All Length (COAL) And Cartridge Base To Ogive (CBTO) – Part 1 by Bryan Litz forBerger Bullets.
Many shooters are not aware of the dramatic effects that bullet seating depth can have on the pressure and velocity generated by a rifle cartridge. Cartridge Overall Length (COAL) is also a variable that can be used to fine-tune accuracy. It’s also an important consideration for rifles that need to feed rounds through a magazine. In this article, we’ll explore the various effects of COAL, and what choices a shooter can make to maximize the effectiveness of their hand loads.
Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI)
Most loading manuals (including the Berger Manual), present loading data according to SAAMI (Sporting Arms and Ammunition Manufacturers’ Institute) standards. SAAMI provides max pressure, COAL and many other specifications for commercial cartridges so that rifle makers, ammo makers, and hand loaders can standardize their products so they all work together. As we’ll see later in this article, these SAAMI standards are in many cases outdated and can dramatically restrict the performance potential of a cartridge.
Bullet seating depth is an important variable in the accuracy equation. In many cases, the SAAMI-specified COAL is shorter than what a hand loader wants to load their rounds to for accuracy purposes. In the case where a hand loader seats the bullets longer than SAAMI specified COAL, there are some internal ballistic effects that take place which are important to understand.
Effects of Seating Depth / COAL on Pressure and Velocity
The primary effect of loading a cartridge long is that it leaves more internal volume inside the cartridge. This extra internal volume has a well known effect; for a given powder charge, there will be less pressure and less velocity produced because of the extra empty space. Another way to look at this is you have to use more powder to achieve the same pressure and velocity when the bullet is seated out long. In fact, the extra powder you can add to a cartridge with the bullet seated long will allow you to achieve greater velocity at the same pressure than a cartridge with a bullet seated short.
When you think about it, it makes good sense. After all, when you seat the bullet out longer and leave more internal case volume for powder, you’re effectively making the cartridge into a bigger cartridge by increasing the size of the combustion chamber. Figure 1 illustrates the extra volume that’s available for powder when the bullet is seated out long.
Before concluding that it’s a good idea to start seating your bullets longer than SAAMI spec length, there are a few things to consider.
Geometry of a Chamber Throat
The chamber in a rifle will have a certain throat length which will dictate how long a bullet can be loaded. The throat is the forward portion of the chamber that has no rifling. The portion of the bullet’s bearing surface that projects out of the case occupies the throat (see Figure 2).
The length of the throat determines how much of the bullet can stick out of the case. When a cartridge is chambered and the bullet encounters the beginning of the rifling, known as the lands, it’s met with hard resistance. This COAL marks the maximum length that a bullet can be seated. When a bullet is seated out to contact the lands, its initial forward motion during ignition is immediately resisted by an engraving force.
Seating a bullet against the lands causes pressures to be elevated noticeably higher than if the bullet were seated just a few thousandths of an inch off the lands.
A very common practice in precision reloading is to establish the COAL for a bullet that’s seated to touch the lands. This is a reference length that the hand loader works from when searching for the optimal seating depth for precision. Many times, the best seating depth is with the bullet touching or very near the lands. However, in some rifles, the best seating depth might be 0.100″ or more off the lands. This is simply a variable the hand loader uses to tune the precision of a rifle.
Here’s something you don’t see every day — a reloading press that has loaded over 1,000,000 rounds of ammo. At the NRA Convention in Dallas in 2018, Redding showcased an old Redding T-7 Turret Press delivered to Sierra Bullets decades ago. 0ne of the very first T-7s made by Redding, this “old warrior” was used by Sierra Bullets to load over 1,000,000 rounds of ammunition in Sierra’s ballistics lab.
Redding T-7 Still Within Spec
After all that loading, Redding tested the press and, remarkably, found that it still remained “within spec”. Redding notes: “This press was subjected to real world reloading wear and stress yet remains within ‘new’ spec after this historic test”. When showcased in Dallas, this Redding turret press was fitted with indicators to show “just how good American steel and craftsmanship remains after what, in a normal situation, would represent numerous lifetimes of use.”
About Redding Reloading
Redding Reloading Equipment has crafted quality, American-made products for the precision handloading market since 1946. Along with single-stage and turret presses, Redding makes great dies. And Redding’s line of tools/accessories includes concentricity gauges, scales, trimmers, powder measures, powder tricklers, cleaning tools, deburring tools, bushings, and many other quality items.
Many shooters prefer to deprime their brass before resizing. That way they can tumble cases or keep primer debris off their main press. To deprime cases before sizing or cleaning you can use a Depriming Die (aka “decapping die”). This pushes out the spent primer without changing the neck or body of a case. Such decapping dies work fine, but they do require the use of a press. Here is a handy alternative — a cool tool that allows you to deprime brass anywhere — no press needed.
Handheld Primer Removal Tool From Frankford Arsenal
This cleverly-designed Hand Deprimer Tool allows you to deprime cartridge cases without a press. This hand-tool from Frankford Arsenal will deprime brass and capture primers conveniently. You can deprime your cases while watching TV or relaxing in your favorite chair.
This device lets you remove spent primers anywhere — no press needed and all the mess (cups/anvils/residue) stays in the capture chamber. This tool comes works with nearly all common case types up to .338 Lapua Magnum. With good leverage, this tool does the job quicklyi and efficiently. Forum members have praised this handy tool, but recommend wearing a thick glove if doing more than 100 cases in a sesssion.
This handy depriming tool is very versatile. With a universal, cylinder-style cartridge-holder, the tool can deprime a wide variety of cartridge types from .20 caliber up to .338 caliber. Three different plastic collets are provided to handle for different diameter cases. Spent primers are captured in a removable spent primer catch tube. Simply twist off the clear catch tube to dump the spent primers. With die-cast metal construction, this tool should last through many thousands of depriming cycles. MSRP is $54.99. Right now it is $44.99 on Amazon with 82% 5-star ratings.
User Modifications — Grip Padding and High-Volume Capture
Many users recommended putting some kind of padding on the grip and front lever to reduce pressure on the fingers. This can be done with a wrap or a rubber covering. In addition, users have adapted the unit with an attached hose and large primer capture jug. If you depriming hundreds of cases at a time, this hose conversion may make sense.
Review from actual owner: “I have owned one of these for about eight years and deprimed over 10,000 cases with this tool. I have never had to replace a single part on it. You will have to adjust the return spring every so often, but that is a very easy task. If you are depriming a LOT of brass, the handle can tear up your hand a bit. Solution: Wear a Mechanics Glove. Easy Peasy! You will NOT regret this purchase.”
How to Adapt Tool for Small Flash Hole Brass
The Frankford Arsenal Deprimer Tool was designed for LARGE flash-hole brass. To deprime brass with small (1.5mm/0.59″) small flash-holes, as found on Lapua .220 Russian and 6mmBR cases, you will need to reduce the pin diameter. A smaller pin is “in development” according to the manufacturer. Frankford Arsenal currently recommends purchasing a replacement pin and “sanding it down” to the smaller diameter. NOTE: This is NOT difficult — simply spin the stock pin in some sandpaper.
A while back, we featured a portable reloading bench built on a Black & Decker Workmate. That proved a VERY popular do-it-yourself project so we’re showing it again, in case you missed it the first time.
Texan Robert Lewis made himself a great portable reloading bench from plywood mounted to a Black & Decker Workmate. The bench, roughly 22″ x 19″ on top, folds up to fit easily in your car’s trunk or behind the seats in a pick-up truck cab. Four recessed bolts hold the wood top section to the collapsible B&D Workmate. The sides and back of the unit are attached to the base with small nails. There is a small shelf (also nailed in place) which can be used to clamp a powder measure or hold a scale. Shown in the photo is a Harrell’s Benchrest measure and Harrell’s single-stage “C” press.
The whole unit can be built for about $65.00 with pine, or $80.00 with oak (as shown). Robert explained: “The Workmate was $40. If someone bought a 2’x4′ sheet of 3/4″ oak plywood, I think it is around $30. Using pine plywood would be about half that. Fasteners were $3. Spar Urethane would be $5.”
Robert told us: “I used a couple ideas I found on the web. The Larry Willis website gave me the idea to use the Black and Decker Workmate as a base. I found the Workmate on sale for $40 and the top is made from oak plywood I had in my shop. I sealed the wood with three coats of Spar Urethane. The whole thing folds into a nice package for transportation to and from the range.”
NOTE: Since we first ran this story, the price of a Black & Decker Workmate WM225 has increased. However you can still pick a WM225 Workmate for under $60.00. Amazon is currently selling WM225 Workmates for $59.58. The next best price we found was $69.61 at Home Depot, still a good price (Lowe’s is charging $94.98).
The U.S. Army Marksmanship Unit (USAMU) has published a great series of reloading “how-to” articles on its Facebook Page. This post covers key factors to consider when loading ammunition for Match Rifles and Service Rifles, with a particular focus on self-loading “gas guns”. Visit the USAMU Facebook Page each Wednesday for other, helpful “Handloading Hump-Day” tips.
We offer some “cardinal rules” to help new gas-gun handloaders with safety and efficiency. These address both Match Rifle and Service Rifle versions of the AR15, M1 Garand, M1A, and M110. However, they can also improve safe reloading for many other auto-loaders such as M1 Carbines, FALs, SIGs, etc. The author distilled these principles many years ago to help focus on the essential aspects of these rifles.
RULE ONE: Service Rifles Are Not Benchrest Rifles
Gas-guns require a relatively loose fit between ammunition and chamber (vs. bolt actions) for safe, smooth operation. Many techniques, such as neck sizing and keeping cartridge headspace quite tight, are popular in the extreme bolt gun accuracy realm. However, they are of little value with Service Rifles, and some could even be hazardous. Before adopting a specialized technique, seriously consider whether it is appropriate and beneficial in a gas-gun.
RULE TWO: Never Compromise Safety to Obtain Accuracy
Example: If choosing a brand of great, but ultra-sensitive match primers offers possibly better accuracy at the risk of slam-fires in your design of rifle, don’t do it! You are issued exactly two eyes and ten fingers (best-case scenario). Risking them trying to squeeze 0.25 MOA better accuracy out of an M1A, etc. simply isn’t worth it.
RULE THREE: Tailor the Precision to Your Individual Skill and Your Rifle’s Potential
This has been addressed here before, but bears repeating for newcomers. If you are struggling to break out of the Marksman Class, or using a CMP M1 “As-Issued,” then laboriously turning the necks of your 600-yard brass is a waste of time. Your scores will improve much faster by practicing or dry-firing. On the other hand, if the reigning champions anxiously check your scores each time you fire an event, a little neck-turning might not be so far-fetched.
Verifying Load Improvements — Accuracy hand-loading involves a wide variety of techniques, ranging from basic to rather precise. Carefully select those which offer a good return on investment for your time and labor. In doubt? Do a classic pilot study. Prepare ammo for at least three or four ten-shot groups with your new technique, vs. the same with your standard ammo. Then, pick a calm day and test the ammo as carefully as possible at its full distance (e.g. 200, 300, or 600 yards) to verify a significant improvement. A little testing can save much labor!
RULE FOUR: Be Your Own Efficiency Expert
Serious Service Rifle shooters generally think of ammunition in terms of thousands of rounds, not “boxes”, or even “hundreds”. Analyze, and WRITE DOWN each step in your reloading process. Count the number of times each case is handled. Then, see if any operations can be dropped or changed without reducing safety or accuracy. Eliminating just two operations saves 2000 steps per 1000 rounds loaded. Conversely, carefully consider any measurable benefits before adding a step to your routine.
RULE FIVE: In Searching for Greater Accuracy with Efficiency, Look for System Changes
For example, instead of marking your 300-yard rounds individually to differentiate them from your 200-yard ammo, would a simple change in primers work? If accuracy is maintained, using brass-colored primers for 200 and silver for 300 provides an indelible indicator and eliminates a step! Similarly, rather than spending hours selecting GI surplus brass for weight and neck uniformity, consider splurging on some known, high-quality imported match brass for your 600-yard loads. Results should be excellent, time is saved, and given limited shooting at 600 yards, brass life should be long.
RULE SIX: Check All Your Primers Before Packaging Your Loaded Ammo
This seems simple and even intuitive. However, many slam-fires (which were much more common when M1s and M1As were the standard) are due, at least in part, to “high” primers. Primers should be seated below flush with the case head. The USAMU has addressed this at length in a previous column, but each round should be checked for properly-seated primers before they are packaged for use.
Three near-equal-weight 7mm bullets with different shapes and bearing surface.
This article, from the USAMU Facebook Page, concerns reloading safety. In the relentless quest for more speed and flatter ballistics, some hand-loaders load way too hot, running charges that exceed safe pressure levels. Hint: If you need a mallet to open your bolt, chances are your load is too hot. Stay within safe margins — your equipment will last longer, and you won’t risk an injury caused by over-pressure. In this article, the USAMU explains that you need to account for bullet shape, diameter, and bearing surface when working up a load. Don’t assume that a load which is safe for one bullet will be safe for another even if both bullets are exactly the same weight.
Today, 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. In fact, diameters 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 and Pressure
Bullet bearing surface length (BSL) is often overlooked when considering maximum safe powder charges and pressures. In Photo 1, note the differences in the bullets’ appearance. All three are 7 mm, 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.
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 inch) 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!
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 deluding.
Note: Due to time constraints, the writer used an approximate, direct measurement approach to assess the bullets’ different BSLs. While fairly repeatable, the results were far from ballistics engineer-grade. Still, they are adequate for this example.
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. You can use comparators on calipers, but be aware that this method may give you deceptive reading — we’ve seen variances just by reversing the comparators on the calipers, because the comparators, typically, are not perfectly round, nor are they machined to precision tolerances.]
Thanks to the U.S. Army Marksmanship Unit for allowing the reprint of this article.
Looking for a faster, easier, and more accurate way to measure bullet positions on your loaded rounds? Check out the Accuracy One Seating Depth Comparator. This unique tool provides a shoulder-to-ogive measurement instead of the traditional cartridge base-to-ogive measurement. The Accuracy One Comparator just might work for you. This unique tool allows a very rapid and secure measurement that provides a precise determination of the bullet seating depth in the case.
Accuracy One Seating Depth Comparator
Product Review by F-Class John
You probably check your loaded ammo by measuring cartridge base to ogive, but have you ever considered there may be a better way? Curt at Accuracy One has considered the question, and after exhaustive research and testing he created the Accuracy One Seating Depth Comparator. As opposed to looking for a base to ogive measurement, this tool measures from the shoulder to ogive, which is arguably the more repeatable number when it comes to accuracy.
Click Arrow to Watch Video Tool Review
As Curt explains, “Well, when you fire a chambered cartridge, the strike from the firing pin first pushes the cartridge forward until it bottoms against the shoulder. The primer is then ignited. What this means is that your seated bullet depth consistency can more accurately be gauged using the dimension from shoulder to ogive. Using this dimension, you effectively eliminate any small variances in your sized case length from the equation”. As a result, it made sense that when he was designing the measurement tool his goal was to create a universal insert that allowed a user a quick, easy, accurate and repeatable process that measures from mid-shoulder to ogive.
The comparator fits cartridges from .22 to .30 Caliber with 0.400″ and larger shoulder diameters. The tool fits so many bullet sizes because of the specific taper that Curt developed. This ensures that any caliber in that range makes good contact along the ogive. As I used this tool and talked to people about it, I kept getting skeptical comments with people asking how it could measure the ogive on that many calibers accurately. I had to remind them that the ogive is not a single point on the bullet but in fact the entire curve from the tip of the bullet to the point it straightens out. As a result, it’s only important that the tool you use is consistent in what point along the ogive it measures and that’s where the Accuracy One Seating Depth Comparator shines. According to Curt, he went through countless iterations on his design until he was able to accurately and repeatably measure all those calibers (.22 to .30).
How to Use the Accuracy One Seating Depth Comparator
Using the comparator is simple. There are alternative methods. The easiest way is to simply zero the indicator, insert a loaded round, note the measurement and compare any future rounds against it for variation. An alternative to this is a method I use. I insert a loaded round and then zero the indicator. This allows you to see the exact variation without mental math (and frankly it’s faster this way). I also use this method to sort loaded rounds for matches in order from shortest to longest ensuring that rounds that measure the same are fired together.
Bonus Option — Measuring Length to Lands with Tool
Another great use for this Accuracy One comparator is to take my initial depth to lands. This helps ensure my seating depth was properly set. Using a case with very light neck tension, I load a bullet, and with a stripped bolt I load and close it. Then I can remove the round and take a measurement, zero the indicator and make a note of it in my book. After that the comparator will remember the new zero until it’s zeroed again and if that happens by accident, I can always reference the number that my round measured and pull on the indicator stem until that number is found and then zero it again. I found this entire process fast, easy and repeatable as I loaded rounds and needed to check for any seating depth variance.
Tool Pricing:
Seating Depth Comparator without Indicator: $65.00
Seating Depth Comparator with Indicator: $115.00
Gauge Stand: $47.00
Purchase Options
You can buy the tool with or without an Digital Indicator. Accuracy One also makes a Primer Depth Gauge. Both Accuracy One tools employ the same digital indicator. This helps save money as you can order the comparator alone if you already have one (either from another Accuracy Tool or another tool).
The Accuracy One Seating Depth Comparator is essentially the same size as the Accuracy One Primer Depth Gauge, so you can even utilize Accuracy One’s primer gauge storage case. There is also an optional stand that I HIGHLY RECOMMEND as it can hold either the seating depth OR primer gauge, making for amazingly simple one-handed operation while you’re loading.
CONCLUSION — Tool Is Precise, Repeatable, and Fast
Overall, this tool left me feeling confident in my depth setting and I found it quick and easy compared to past methods. At the end of the day there are several ways to skin the proverbial cat when it comes to measuring seating depth. But if you’re looking for what just might be the most accurate, consistent and speediest method, give the Accuracy One Seating Depth Comparator a try.
We are re-publishing this article at the request of Forum members who found the information very valuable. If you haven’t read this Safety Tip before, take a moment to learn how you can inspect your fired brass to determine if there may be a potential for case separation. A case separation can be dangerous, potentially causing serious injury.
On the respected Riflemans’ Journal blog there was an excellent article about Cartridge Case-Head Separation. In this important article, Journal Editor GS Arizona examined the causes of this serious problem and explained the ways you can inspect your brass to minimize the risk of a case-head separation. As cases get fired multiple times and then resized during reloading, the cases can stretch. Typically, there is a point in the lower section of the case where the case-walls thin out. This is your “danger zone” and you need to watch for tell-tale signs of weakening.
The photo below shows a case sectioned so that you can see where the case wall becomes thinner near the web. You can see a little arrow into the soot inside the case pointing to the thinned area. This case hadn’t split yet, but it most likely would do so after one or two more firings.
Paper Clip Hack for Detecting Problems
The article provided a great, easy tip for detecting potential problems. You can use a bent paper clip to detect potential case wall problems. Slide the paper clip inside your case to check for thin spots. GS Arizona explains: “This simple little tool (bent paper clip) will let you check the inside of cases before you reload them. The thin spot will be immediately apparent as you run the clip up the inside of the case. If you’re seeing a shiny line on the outside and the clip is really hitting a thin spot inside, it’s time to retire the case. If you do this every time you reload, on at least 15% of your cases, you’ll develop a good feel for what the thin spot feels like and how it gets worse as the case is reloaded more times. And if you’re loading the night before a match and feel pressured for time — don’t skip this step!”
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A while back, we featured a portable reloading bench built on a Black & Decker Workmate. That proved a VERY popular do-it-yourself project so we’re showing it again, in case you missed it the first time.
Purchase Options
On the respected Riflemans’ Journal blog there was an excellent article about Cartridge Case-Head Separation. In this important article, Journal Editor GS Arizona examined the causes of this serious problem and explained the ways you can inspect your brass to minimize the risk of a case-head separation. As cases get fired multiple times and then resized during reloading, the cases can stretch. Typically, there is a point in the lower section of the case where the case-walls thin out. This is your “danger zone” and you need to watch for tell-tale signs of weakening.
