This was one of our 25 Most Popular Articles in 2017. We’re repeating it for those of you who may have missed it the first time around. These diagrams were created by the South Texas Shooting Marksmanship Training Center (STMTC).
There was an excellent article about Mirage created for the South Texas Marksmanship Training Center (STMTC). This article explains what causes mirage and how mirage can move the perceived aiming point on your target. Most importantly, the article explains, in considerable detail, how you can “read” mirage to discern wind speeds and wind directions.
Mirage Is Your Friend
While hot days with lots of mirage can be frustrating, mirage can reveal how the wind is flowing (and changing). If you learn how to recognize and read mirage patterns, you can use that information to shoot higher scores. That’s why many leading long-range shooters tell us: “Mirage is your friend.” As the STMTC article explained: “A mirage condition is not a handicap, since it offers a very accurate method of perceiving small wind changes[.]”
Mirage Illustrated with Diagrams
With simple but effective graphic illustrations, this is one of the best explanations of mirage (and mirage reading) we have found on the internet. This is a “must-read” for any serious competitive shooter. Here is a brief sample from the article, along with an illustration. NOTE: the full article is six times longer and has 8 diagrams.
The term “mirage” as used by the shooter does not refer to a true mirage, but to heat waves and the refraction of light as it is bent passing through air layers of different density. Light which passes obliquely from one wind medium to another it undergoes an abrupt change in direction, whenever its velocity in the second medium is different from the velocity in the first wind medium; the shooter will see a “mirage”.
The density of air, and therefore its refraction, varies with its temperature. A condition of cool air overlaying warm air next to the ground is the cause of heat waves or “mirage”. The warm air, having a lower index of refraction, is mixed with the cooler air above by convection, irregularly bending the light transmitting the target image to the shooter’s eye. Figure 1 shows (greatly exaggerated) the vertical displacement of the target image by heat waves.
Heat waves are easily seen with the unaided eye on a hot, bright day and can be seen with spotting scope on all but the coldest days. To observe heat waves, the scope should be focused on a point about midway to the target. This will cause the target to appear slightly out of focus, but since the high power rifle shooter generally does not try to spot bullet holes, the lack in target clarity is more than compensated by clarity of the heat waves.
Story tip from Boyd Allen. We welcome reader submissions.
The 2025 Southwest Nationals (SWN) start 2/12/2025 at the Ben Avery Range outside Phoenix, AZ. The big event starts with a 600-yard Mid-Range Match. Many of the nation’s most talented F-Class and sling shooters will be there. But no matter what your skill level, it is still possible to make major mistakes that can spoil the day and/or put you out of the running for the entire match. This article aims to help competitors avoid the big errors/oversights/failures, aka “train wrecks”, that can ruin a match.
Photo by Sherri Jo Gallagher.
In any shooting competition, you must try to avoid major screw-ups that can ruin your day (or your match). In this article, past F-TR National Mid-Range and Long Range Champion Bryan Litz talks about “Train Wrecks”, i.e. those big disasters (such as equipment failures) that can ruin a whole match. Bryan illustrates the types of “train wrecks” that commonly befall competitors, and he explains how to avoid these “unmitigated disasters”.
Urban Dictionary “Train Wreck” Definition: “A total @#$&! disaster … the kind that makes you want to shake your head.”
Success in long range competition depends on many things. Those who aspire to be competitive are usually detail-oriented, and focused on all the small things that might give them an edge. Unfortunately it’s common for shooters lose sight of the big picture — missing the forest for the trees, so to speak.
Consistency is one of the universal principles of successful shooting. The tournament champion is the shooter with the highest average performance over several days, often times not winning a single match. While you can win tournaments without an isolated stellar performance, you cannot win tournaments if you have a single train wreck performance. And this is why it’s important for the detail-oriented shooter to keep an eye out for potential “big picture” problems that can derail the train of success!
Train wrecks can be defined differently by shooters of various skill levels and categories. Anything from problems causing a miss, to problems causing a 3/4-MOA shift in wind zero can manifest as a train wreck, depending on the kind of shooting you’re doing.
Below is a list of common Shooting Match Train Wrecks, and suggestions for avoiding them.
1. Cross-Firing. The fastest and most common way to destroy your score (and any hopes of winning a tournament) is to cross-fire. The cure is obviously basic awareness of your target number on each shot, but you can stack the odds in your favor if you’re smart. For sling shooters, establish your Natural Point of Aim (NPA) and monitor that it doesn’t shift during your course of fire. If you’re doing this right, you’ll always come back on your target naturally, without deliberately checking each time. You should be doing this anyway, but avoiding cross-fires is another incentive for monitoring this important fundamental. In F-Class shooting, pay attention to how the rifle recoils, and where the crosshairs settle. If the crosshairs always settle to the right, either make an adjustment to your bipod, hold, or simply make sure to move back each shot. Also consider your scope. Running super high magnification can leave the number board out of the scope’s field view. That can really increase the risk of cross-firing.
2. Equipment Failure. There are a wide variety of equipment failures you may encounter at a match, from loose sight fasteners, to broken bipods, to high-round-count barrels that that suddenly “go south” (just to mention a few possibilities). Mechanical components can and do fail. The best policy is to put some thought into what the critical failure points are, monitor wear of these parts, and have spares ready. This is where an ounce of prevention can prevent a ton of train wreck. On this note, if you like running hot loads, consider whether that extra 20 fps is worth blowing up a bullet (10 points), sticking a bolt (DNF), or worse yet, causing injury to yourself or someone nearby.
3. Scoring/Pit Malfunction. Although not related to your shooting technique, doing things to insure you get at least fair treatment from your scorer and pit puller is a good idea. Try to meet the others on your target so they can associate a face with the shooter for whom they’re pulling. If you learn your scorer is a Democrat, it’s probably best not to tell Obama jokes before you go for record. If your pit puller is elderly, it may be unwise to shoot very rapidly and risk a shot being missed (by the pit worker), or having to call for a mark. Slowing down a second or two between shots might prevent a 5-minute delay and possibly an undeserved miss.
Photo by Sherri Jo Gallagher.
4. Wind Issues. Tricky winds derail many trains. A lot can be written about wind strategies, but here’s a simple tip about how to take the edge off a worse case scenario. You don’t have to start blazing away on the command of “Commence fire”. If the wind is blowing like a bastard when your time starts, just wait! You’re allotted 30 minutes to fire your string in long range slow fire. With average pit service, it might take you 10 minutes if you hustle, less in F-Class. Point being, you have about three times longer than you need. So let everyone else shoot through the storm and look for a window (or windows) of time which are not so adverse. Of course this is a risk, conditions might get worse if you wait. This is where judgment comes in. Just know you have options for managing time and keep an eye on the clock. Saving rounds in a slow fire match is a costly and embarrassing train wreck.
5. Mind Your Physical Health. While traveling for shooting matches, most shooters break their normal patterns of diet, sleep, alcohol consumption, etc. These disruptions to the norm can have detrimental effects on your body and your ability to shoot and even think clearly. If you’re used to an indoor job and eating salads in air-conditioned break rooms and you travel to a week-long rifle match which keeps you on your feet all day in 90-degree heat and high humidity, while eating greasy restaurant food, drinking beer and getting little sleep, then you might as well plan on daily train wrecks. If the match is four hours away, rather than leaving at 3:00 am and drinking five cups of coffee on the morning drive, arrive the night before and get a good night’s sleep.”
Keep focused on the important stuff. You never want to lose sight of the big picture. Keep the important, common sense things in mind as well as the minutia of meplat trimming, weighing powder to the kernel, and cleaning your barrel ’til it’s squeaky clean. Remember, all the little enhancements can’t make up for one big train wreck!
With the major Southwest Nationals competition just 3 days away we thought our readers would enjoy a look at a contemporary F-TR competition rifles campaigned by a talented, multi-discipline lady shooter. Texan Tracy Slayton is a gifted action pistol and 3-Gun competitor who now also competes in F-Class, F-TR Division. Under F-Class rules, F-TR shooters are limited to two caliber types: .223 Rem (5.56 NATO) and .308 Win (7.62x51mm).
A while back, on Facebook, Tracy posted a nice training session with her Krieger-barreled .308 Winchester F-TR rifle. Her rifle features a McMillan composite stock with a SEB JoyStick bipod attached up front. The optic is a Kahles SFP 1/8 MOA zoom optic (10-50x50mm we believe). You can watch her shooting video HERE on her Facebook page. She used a battery-powered, Chamber Chiller fan unit to cool the barrel.
On her Facebook page, Tracy posted: “Very, very windy day today but pulled off a 444/450 18X which is a High Master score. My Krieger barrel is the bomb and my Kahles scope allows me to see that target at 600 yards clearly. My Chamber Chiller really cools my barrel down in between matches and my Stiller action is as smooth as butter.”
Click Photo for short video of Tracy’s shooting session, with shots called on audio:
Match-Winning F-TR .308 Win Load INFO
Texan Tracy Slayton (featured above) did not supply her .308 Win load data for this article. However, we’ve got something even better! For our readers who compete in F-TR, we obtained .308 Win F-TR load information from top F-TR shooter, Peter Johns. A U.S. Navy veteran, Peter won the 2020 Berger SW Nationals F-TR title, after finishing second at that same event in 2019. Here is Peter’s load profile, a very good place to start for any .308 Win F-TR shooter…
F-TR .308 Win Match Load and Reloading Methodology
Loading for .308 Win F-TR — Do What Matters
Peter told us: “My loading technique has evolved almost full circle from where I started. I went from the basics to doing every step a person could conceive. Then I decided to start testing all the different steps to see what didn’t matter or made things worse. I am now back to almost no steps in my reloading process.
I don’t clean brass anymore. I just wipe the case off, lube, size, prime, and load. I anneal when I feel the necks getting inconsistent when seating the bullets. I pre-load all my ammo for matches. I tried seating them at the match but I didn’t find it to matter on the score card and it takes my focus away from conditions.
Peter’s 2020 SWN-winning .308 Win load consists of Berger 200.20X bullets, Lapua Palma brass, Federal 205M primers, and Varget powder. Peter revealed: “The Berger 200-grainers are running in the mid-2600 fps range. I have tried them much faster but found the best consistency at this speed.”
Peter measures powder to the kernel and also weighs/sorts other components. He runs Berger 200.20X bullets slightly off the lands in a 0.170 freebore chamber. Notably he tests a variety of powders, ascertaining each barrel’s particular preference: “In the last few years I have tried N140, N150, H4895, and Varget. I think they are all good powders for F-TR and the 200.20X bullet. This year I was using Varget. At the 2018 SWN I placed 4th with H4895, in 2019 SWN I got 2nd with N140. I find what powder my particular barrel likes best. I also test CCI BR4 and Fed 205M to see which my rifle likes best. This year I was using Fed 205M. I have been using Lapua Palma brass and it seems to last forever.” Peter full-length sizes with a Redding bushing FL die. He seats his Berger bullets with a Wilson inline seater.
Berger Bullets on SALE Now at Creedmoor Sports
Right now Creedmoor Sports is running a major Berger bullet sale. You’ll find many .30-cal Berger match bullet types that work great for .308-caliber F-TR rigs like today’s featured rifle. Berger .30-cal match bullets, ranging from 155gr to 220gr in weight, are currently in stock with many types discounted.
In addition to the .30-cal Bergers, Creedmoor Sports has significant supplies of Berger .17, .20, .223, .243 (6mm), .257, .264 (6.5mm), .270, and .284 (7mm) caliber bullets in stock now at good prices. There are a wide variety of bullet types for various discplines. Choose target hybrids, varmint bullets, Elite Hunters or other bullet types for your next match or hunt.
Progressive reloading presses offer shooters speed and efficiency in producing custom-tailored rifle and pistol ammunition. However, there is a wide choice of Progressive Presses and a bewildering array of options to consider. In this video, the 6.5 Guys and UltimateReloader.com’s Gavin Gear provide an overview of the leading Progressive Presses on the market along with key considerations for precision rifle shooters. If you are considering getting a Progressive for rifle ammo reloading, you should watch this informative, 25-minute video.
10 Tips for Reloading Rifle Ammo on a Progressive Press:
1. Make sure the brass is very clean. Don’t mix old range pick-up brass with newer brass.
2. Apply a thin, spray lube to all cases before the sizing/loading cycle.
3. Consider priming your brass separately (with a hand or bench tool) before the operation. Then inspect the primers before loading powder and bullets.
4. Always wear eye protection when loading with the Progressive, particularly if you are priming cases.
5. With masking tape, mark the powder measure/dropper with the powder type and cartridge charge weight. Check the charge mass multiple times (see below).
6. Cycle a few cases, sizing and adding powder but NOT seating bullets. Weigh the powder charges to ensure the powder measure is dispensing the correct charge. Sometimes this will change a couple tenths as it “settles down” after the first few charges.
7. Check the brass for shoulder bump and bullet seating depth carefully for the first few rounds, then check again periodically.
8. Try to maintain a steady pace and operate the handle the same way every time.
9. Visually inspect the powder charge in each case (before bullet seating), and use a lock-out die if your Progressive Press has enough stations.
10. Never, ever mix pistol and rifle powders! If you have previously loaded pistol ammo with your Progressive, make sure ALL the powder (every flake and kernel) is removed from all parts of the powder-dropping system before you add rifle powder.
Visit these sites for more Reloading and Precision Shooting Videos:
Do you have some ammo that got loaded incorrectly, perhaps with the wrong powder? Then you’ll want to disassemble the ammo for safety’s sake. You can use an impact puller to do this task, but if you have more than a dozen rounds or so, you may prefer to use a collet-style bullet puller. These work very quickly and positively, making quick work of big jobs. The efficiency of the collet-style puller is worth the investment if you frequently disassemble ammo. These devices retail for under $35.00 (collets sold separately). Normally, you’ll need a specific collet for each bullet diameter. But collets are not that costly, so this isn’t a big deal, particularly if you only load a few calibers, such as .223, 6mm, and .308.
Hornady and RCBS use different mechanisms to tighten the collet around the bullet. On the red lever Hornady Cam-Lock Bullet Puller, a lever-arm on the top of the bullet puller serves to tighten the collet around the bullet. Simply rotate the lever from the vertical to the horizontal position to grab the bullet. Lower the ram to remove the case. The bullet will drop out when you return the lever arm to the vertical position. This is demonstrated in the video below:
Hornady Cam-Lock Bullet Puller Demonstrated
Collet bullet-pullers resemble a loading die with a lever or handle on the top. They screw into a standard reloading press. Hornady and RCBS both make collet-style bullet pullers. They use the same basic principle — the device tightens a collet around the bullet, and then the bullet is separated from the case by lowering the press ram. NOTE: Collet pullers may leave small marks on your bullets, unlike impact (kinetic) pullers.*
Like the Hornady tool, the RCBS Bullet Puller employs a collet to grab the bullet. However, the RCBS tool tightens the collet in a different way. The head of the RCBS tool is threaded internally. By rotating the lever arm clockwise in a horizontal circle you squeeze the collet around the bullet. To remove the bullet, after lowering the press ram, simply spin the lever arm back in the opposite direction. The use of the RCBS tool is demonstrated in these two videos:
RCBS Collet Bullet Puller Demonstrated:
WARNING: When removing bullets from loaded cartridges, always make sure there are no obstructions or debris in your shell-holder or under the loaded round. NEVER engage a primer seating accessory on your press when working with loaded rounds. You can cause a round to discharge by contacting the primer! Also, we recommend you keep your head and torso away from the bullet puller tool at all times.
*By contrast, impact pullers rarely mark bullets, particularly if you put a little bit of foam or paper wadding in the closed end of your impact puller. When dismantling loaded rounds, powder kernels can get trapped in the wadding, so you should remove and replace the wadding before changing to cartridges loaded with a different powder type (assuming you intend to save the powder).
Here is Ernie Bishop’s pride and joy, a specialty pistol nicknamed “Batman” because the black carbon-fiber stock looks like the Batmobile. This is one sophisticated handgun. Complete with scope, the Batman pistol weighs under 7.5 pounds, thanks to the ultra-light stock. The carbon stock is 6 inches wide at the fore-end, yet weighs just one pound. Ernie tells us: “This gun shoots amazing and is easy to shoot especially with my SEB MAX Rest.” After these photos were taken, Ernie added a “field-usable rear-grip stock so [he could] shoot it prone from a bipod as well.”
The Batman pistol is chambered for the 6mm “Long Dasher”, a 6mm 40°-shouldered variant of the 6.5×47 Lapua. Ernie loads Berger 105gr Hybrid bullets pushed by Hodgdon H4350 powder.
Gun Specifications The gun, crafted by Eric Wallance of Nawaka Firearms, features an XP-100 action, Jewell trigger, and 15″-long, Brux 1:8″-twist barrel with aluminum muzzle brake. Interestingly, this gun does not have a traditional recoil lug. Instead, gunsmith Wallace milled out a lug from the bottom of the XP-100 action to save weight. On top of the action, the rig carries a Sightron Inc S-III 6-24X56mm scope in Kelbly rings on a custom +20 MOA rail.
Long Dasher Wildcat
Shown at right is a “Long Dasher” 40° wildcat created by Forum member Sunbuilder. This is very similar to Ernie Bishop’s chambering, though there may be small variations related to reamer design (such as freebore). Sunbuilder’s 6-6.5×47 Improved (aka “Long Dasher”) reamer was made by Dave Kiff of Pacific, Tool & Gauge. This wildcat cartridge adds about 2.0 grains capacity to the 6.5×47 necked down to 6mm. The case certainly is impressive with that 40° shoulder. We’re just waiting for the tactical guys to starting run this improved cartridge with its original 6.5mm bore.
Here are three FIVE-shot groups at 500 yards, shot by Ernie’s Batman pistol. The first 5-shot group is marked with pink dots, the second with green dots, and the third is measured with the calipers:
When he measures his loads or sorts bullets by weight, Forum Member Boyd Allen often employs his trusty RCBS 10-10 balance beam scale (although he does have handy digital scales as well). He finds that the balance beam scale works predictably, time after time, and it doesn’t suffer from the drift and calibration issues that plague some of the less expensive electronic scales on the market.
To make it easier to see the balance point, Boyd has adapted a magnifying glass with a mirror. This makes the end of his balance beam easier to view from his normal position on the bench. Boyd explains: “This set-up uses a cheap magnifier with positioning arms that was probably designed to hold and magnify small objects while soldering them. I think that it came from Harbor Freight many years ago. The mirror lets you look at the scale as if is was at eye level, and of course the magnifier makes the image easier to see.”
If you have a balance beam scale, we suggest you try this simple enhancement. We predict you’ll find the magnifier speeds up the process with enhanced assurance of your load weight.
The United States Postal Service allows shipment of long-barreled rifles and shotguns via the U.S. Mail. However, regular citizens who do not possess an FFL are NOT allowed to mail handguns at all.* For handguns (all pistols and revolvers), you must use UPS or FedEX and ship FROM an FFL business in most situations.
432.1 General
Mailers must comply with the Gun Control Act of 1968, all of the provisions of postal law in 18 U.S.C. 1715, and all other all federal and state regulations and local ordinances affecting the movement of firearms. The following also applies:
a. The Postal Service may require the mailer to open parcels containing firearms or air guns or give written certification that the weapon is unloaded and not concealable (see note 1).
b. Short-barreled rifles or shotguns that can be concealed on the person are non-mailable.
c. No markings of any kind that indicate the nature of the contents may be placed on the outside wrapper or container of any mailpiece containing firearms.
d. Mailable matter must be properly and securely packaged within the general packaging requirements in DMM 601.1-7.
e. Except for shipments between licensed dealers, manufacturers, or importers, all regulated firearms must be mailed using a USPS product or Extra Service that provides tracking and signature capture at delivery (see note 2).
432.3 Rifles and Shotguns
Except under 431.2, unloaded rifles and shotguns are mailable. Mailers must comply with the rules and regulations under 27 CFR, Part 478, as well as state and local laws. The mailer may be required by the USPS to establish, by opening the parcel or by written certification, that the rifle or shotgun is unloaded and not ineligible for mailing (see note 1). The following conditions also apply:
a. Subject to state, territory, or district regulations, rifles and shotguns may be mailed without restriction when intended for delivery within the same state of mailing. These items must:
1. Bear a “Return Service Requested” endorsement.
2. Be mailed using a class of mail, product, or Extra Service that provides tracking and signature capture at delivery.
b. A rifle or shotgun owned by a non-FFL may be mailed outside the owner’s state of residence by the owner to himself or herself, in care of another person in the other state where he or she intends to hunt or engage in any other lawful activity. These mailpieces must:
1. Be addressed to the owner.
2. Include the “in the care of” endorsement immediately preceding the name of the applicable temporary custodian.
3. Be opened by the rifle or shotgun owner only.
4. Be mailed using a class of mail, product, or Extra Service that provides tracking and signature capture at delivery.
d. Mailing of rifles and shotguns between licensed FFL dealers, manufacturers, or importers are not restricted. The Postal Service recommends that these items be mailed using a class of mail, product, or Extra Service that provides tracking and signature capture at delivery.
e. Except as described in 432.3a, licensed curio and relic collectors may mail firearms meeting the definition of curios or relics under 27 CFR 478.11 domestically to licensed FFL curio and relic collectors in any state. These items must be mailed using a class of mail, product, or Extra Service that provides tracking and signature capture at delivery.
Many novice hand-loaders believe that neck bushing Inside Diameter (ID) size is the only important factor in neck tension. In fact, many different things will influence the grip on your bullet and its ability to release from the case neck. To learn more about neck tension and “case grip”, take the time to read this article carefully. We bet you’ll gain knowledge that will let you load more accurate ammo, with better ES/SD.
Editor: Guys, this is a VERY important article. You really should read it over carefully, twice. Variations in the force required to release a bullet can significantly affect accuracy and ES/SD. You really need to know how the grip on bullet can be altered by many different factors.
Neck Tension (i.e. Grip on Bullets) Is a Complex Phenomenon
While we certainly have considerable control over neck tension by using tighter or looser bushings (with smaller or bigger Inside Diameters), bushing size is only one factor at work. It’s important to understand the multiple factors that can increase or decrease the resistance to bullet release. Think in terms of overall brass-on-bullet “grip” instead of just bushing size (or the internal neck diameter in non-bushing full-length sizing dies).
Bullet grip is affected by many things, such as:
1. Neck-wall thickness.
2. Amount of bullet bearing surface (shank) in the neck.
3. Surface condition inside of neck (residual carbon can act as a lubricant; ultrasonic cleaning makes necks “grabby”).
4. Length of neck (e.g. 6mmBR neck vs. 6mm Dasher).
5. Whether or not the bullets have an anti-friction coating.
6. The springiness of the brass (which is related to degree of work-hardening; number of firings etc.)
7. The bullet jacket material.
8. The outside diameter of the bullet and whether it has a pressure ridge.
9. Time duration between bullet seating and firing (necks can stiffen with time).
10. How often the brass is annealed.
11. Amount (length) of neck sized (e.g. you can size only half the neck).
12. Interior diameter of bushing, or neck section of non-bushing die. – and there are others…
One needs to understand that bushing size isn’t the beginning and end of neck tension questions, because, even if bushing size is held constant, the amount of bullet “grip” can change dramatically as the condition of your brass changes. Bullet “grip” can also change if you alter your seating depth, and it can even change if you ultrasonically clean your cases.
6-time U.S. National Long-Range Champion John Whidden adds: “Our tests show us that the condition of the necks in regards to lubed or not, carbon inside or not, squeaky clean or not, etc., matter even more than the size of the bushing used. An ultrasonically cleaned or brand new dry case neck make for some quite high seating force.”
In our Shooters’ Forum a reader asked: “How much neck tension should I use?” This prompted a lengthy Forum discussion in which other Forum members recommended a specific number based on their experience, such as .001″, .002″, or .003″. These numbers, as commonly used, correspond to the difference between case-neck OD after sizing and the neck OD of a loaded round, with bullet in place. In other words, the numbers refer to the nominal amount of interference fit (after sizing).
While these commonly-used “tension numbers” (of .001″, .002″ etc.) can be useful as starting points, neck tension is actually a fairly complex subject. The actual amount of “grip” on the bullet is a function of many factors, of which neck-OD reduction during sizing is just one. Understanding these many factors will help you maintain consistent neck tension as your brass “evolves” over the course of multiple reloadings.
Seating Depth Changes Can Increase or Decrease Grip on Bullet
You can do this simple experiment. Seat a boat-tail bullet in your sized neck with .150″ of bearing surface (shank) in the neck. Now remove the bullet with an impact hammer. Next, take another identical bullet and seat it with .300″ of bearing surface in another sized case (same bushing size/same nominal tension). You’ll find the deeper-seated bullet is gripped much harder.
Neck-Wall Thickness is Important Too
I have also found that thinner necks, particularly the very thin necks used by many 6mm PPC benchrest shooters, require more sizing to give equivalent “grip”. Again, do your own experiment. Seat a bullet in a case turned to .008″ neckwall thickness and sized down .003″. Now compare that to a case with .014″ neckwall thickness and sized down .0015″. You may find that the bullet in the thin necks actually pulls out easier, though it supposedly has more “neck tension”, if one were to consider bushing size alone.
In practical terms, because thick necks are less elastic than very thin necks, when you turn necks you may need to run tighter bushings to maintain the same amount of actual grip on the bullets (as compared to no-turn brass). Consequently, I suspect the guys using .0015″ “tension” on no-turn brass may be a lot closer to the guys using .003″ “tension” on turned necks than either group may realize.
Toward a Better Definition of Neck Tension
As a convenient short-cut, we tend to describe neck tension by bushing size alone. When a guy says, “I run .002 neck tension”, that normally means he is using a die/bushing that sizes the necks .002″ smaller than a loaded round. Well we know something about his post-sizing neck OD, but do we really have a reliable idea about how much force is required to release his bullets? Maybe not… This use of the term “neck tension” when we are really only describing the amount of neck diameter reduction with a die/bushing is really kind of incomplete.
My point here is that it is overly simplistic to ask, “should I load with .001 tension or .003?” In reality, an .001″ reduction (after springback) on a thick neck might provide MORE “grip” on a deep-seated bullet than an .003″ reduction on a very thin-walled neck holding a bullet with minimal bearing surface in the neck. Bushing ID is something we can easily measure and verify. We use bushing size as a descriptor of neck tension because it is convenient and because the other important factors are hard to quantify. But those factors shouldn’t be ignored if you want to maintain consistent neck tension for optimal accuracy.
Consistency and accuracy — that’s really what this all about isn’t it? We want to find the best neck tension for accuracy, and then maintain that amount of grip-on-bullet over time. To do that you need to look not only at your bushing size, but also at how your brass has changed (work-hardened) with time, and whether other variables (such as the amount of carbon in the neck) have changed. Ultimately, optimal neck tension must be ascertained experimentally. You have to go out and test empirically to see what works, in YOUR rifle, with YOUR bullets and YOUR brass. And you may have to change the nominal tension setting (i.e. bushing size) as your brass work-hardens or IF YOU CHANGE SEATING DEPTHS.
Remember that bushing size alone does not tell us all we need to know about the neck’s true “holding power” on a bullet, or the energy required for bullet release. True bullet grip is a more complicated phenomenon, one that is affected by numerous factors, some of which are very hard to quantify.
The Shooting Sports USA website includes two excellent articles about the basics of metallic cartridge reloading. These two articles provide an excellent summary of the key procedures. If you are new to reloading, we recommend you read both articles:
Part II is particularly helpful because it explains the entire reloading process step-by-step, with 14 listed steps. The author notes: “In this, the second installment on metallic cartridge reloading, we’ll follow the sequence of steps involved in reloading a rifle cartridge and refining a metallic cartridge load. These steps are based on the use of a single-stage reloading press and a separate priming tool.”
Much important advice is provided as this article runs through the 14 Steps of Reloading. For example, when explaining Step 13, Bullet Seating, the article states:
“Proper seating depth is critical. Too much bullet protrusion and the cartridge may not work through the gun’s magazine, or it may fail to chamber. Too little and the bullet intrudes excessively into the powder chamber, decreasing volume and raising pressure. Neck tension is also important; any bullet that fails to seat with some resistance may be held only loosely by the neck and may be driven back into the case when the round is chambered, especially in semi-automatic arms.”
Important Guide to Detecting Over-Pressure Signs in Brass
As an example of the invaluable advice provided in these two articles, here’s a sample from Part II that explains how to determine if your load is over-pressure. We recommend that EVERY reader read this twice. There are more things to consider than a stiff bolt lift. You need to inspect cartridges very carefully: