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 regularly for other, helpful reloading and marksmanship 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!
This video explains the procedure for ordering an M1 Garand from the CMP.
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.
The 6mmBR Norma cartridge has spawned many great variants in multiple calibers: 6mm Dasher, 6BRA, 22 BR, 22 Dasher, 30 BR and others. This article is about a handsome 22 BR Rem-action varmint rig.
Richard Franklin (who operated Richard’s Custom Rifles prior to his retirement), has built scores of varmint rifles, in many different calibers. One of Richard’s all-time favorite varmint rifles is a 1:14″-twist, 22 BR built on his Model 11 stock in laminated Black Walnut and fiddleback maple. Richard says the rifle is versatile and deadly accurate out to 400 yards. Richard uses a Leupold 8.5-25x50mm LRT with varmint reticle.
Richard’s 22 BR Varmint Rifle with Lilja Barrel
Richard tells us: “[Shown above] is my light walking varminter. It’s built on a blue-printed Stainless Steel Remington 700 short action and chambered as a no-turn 22 BR for Lapua brass. The bolt handle is a Dave Kiff replacement and I’ve fitted a Jewel BR trigger with bottom safety. The barrel is a Lilja, 1:14″ #6 contour with a muzzle diameter of .750″. I shoot the 40gr V-Max bullets in the rifle at 4000 FPS. It’s tough on hogs if you don’t try them too far. 400 yards is about the max with it.
Accuracy is outstanding and with Roy, Mike, my grandson and myself shooting this rifle I don’t believe it has missed more than three hogs out of over 100 we shot at one summer. This rifle is carried in a ceiling rack in the truck where it’s handy and is used by the first person that grabs it when a hog is sighted if we are moving between setups. The Varmint reticle on the Leupold (shown below) is nice for quick hold-overs as you change distances.”
At right is a another Franklin Model 11 stock in Birdseye maple. That photo shows the details of the thumbhole stock.
Editor’s Note: We have shot a 1:8″-twist 22 BR in varmint matches and it was very accurate with 80gr bullets. It actually shot flatter out to 500 yards than our 6mmBR running 105-grainers. If we were to build a new long-range, bolt-action varmint rifle it would probably be a 22 BRA, essentially a 22 BR with 40° shoulder. That gives you a very stable cartridge with a bit more capacity. The 22 BRA retains a longer neck compared to the 22 Dasher, which is also an excellent cartridge — versatile and accurate.
22 BR Rivals 22-250 Performance
With bullets in the 40gr to 60gr weight range, the 22 BR gives up very little in velocity to a 22-250, despite burning quite a bit less powder (30-32 grains for the 22 BR vs. 35-38 grains for the 22-250). With a match-quality chamber, the 22 BR will probably have an edge in accuracy over a 22-250, and you should experience longer barrel life. Here are some recommended 22 BR loads for 40-60gr bullets:
Today is May 5, aka “Cinco De Mayo”. This day is celebrated as a notable day in Mexican history when Mexican forces scored a major victory over French military forces. To help celebrate Cinco De Mayo in 2026, Midsouth Shooters is running a major sale on Aguila ammunition components, many of which were manufactured in Mexico.
The sale includes rimfire ammo, centerfire rifle and pistol ammo, shotgun ammunition and primers. Here are some of the dozens of Aguila items on sale this week:
Rifle ammo on sale includes: .22 LR, .223 Rem, 6.5 Creedmoor, .30 Carbine, 7.62×51 (.308 Win)
Pistol ammo on sale includes: .22 LR, .32 Auto, .32 S&W, 9mm Luger, .38 Super, .38 SPL, .357 Magnum, .44 Magnum, .45 ACP, .45 Colt
Cinco De Mayo History Cinco de Mayo, observed on May 5th, commemorates the Mexican army’s 1862 victory over French forces at the Battle of Puebla. Led by General Ignacio Zaragoza, outnumbered Mexican troops defeated a superior European army, providing a major morale boost. The History of War notes: “On this day in 1862, a small force of locals – many of whom were ill-equipped and not trained soldiers – fought back against thousands of French troops at Puebla, a small town in central Mexico. The battle lasted all day and resulted in a victory for the Mexicans after the French army retreated.”
While not a federal holiday in Mexico, Cinco de Mayo has evolved into a widespread celebration of Mexican culture, heritage, and identity. Often mistaken for Mexican Independence Day (September 16), Cinco de Mayo (as a day of celebration) gained prominence in the U.S. during the 1960s and 70s.
Want to improve your understanding of Ballistics, Bullet Design, Bullet Pointing, and other shooting-related tech topics? Well here’s a treasure trove of gun expertise. Applied Ballistics offers dozens of FREE tech articles on its website. Curious about Coriolis? — You’ll find answers. Want to understand the difference between G1 and G7 BC? — There’s an article about that.
“Doc” Beech, technical support specialist at Applied Ballistics says these articles can help shooters working with ballistics programs: “One of the biggest issues I have seen is the misunderstanding… about a bullet’s ballistic coefficient (BC) and what it really means. Several papers on ballistic coefficient are available for shooters to review on the website.”
Credit Shooting Sports USA Editor John Parker for finding this great resource. John writes: “Our friends at Applied Ballistics have a real gold mine of articles on the science of accurate shooting on their website. This is a fantastic source for precision shooting information[.] Topics presented are wide-ranging — from ballistic coefficients to bullet analysis.”
Here are five (5) of our favorite Applied Ballistics articles, available for FREE to read online. There are dozens more, all available on the Applied Ballistics Education Webpage. After Clicking link, select Plus (+) Symbol for “White Papers”, then find the article(s) you want in the list. For each selection, then click “Download” in the right column. This will send a PDF version to your device.
by Sierra Bullets Ballistic Technician Philip Mahin for Sierra Bullets Blog
A lot of calls that come into the Sierra Customer Service Center are made by shooters [of retirement age]. Most of the time the shooter used to reload back when they were [younger] and stopped in order to raise a family, pursue a career, or both. Maybe their father or grandfather taught them back in the day and they are looking for an answer to the new whatchamacallit they found on the internet. The point is they are coming back to it because it was fun.
Reloading Can Provide Stress Relief
As a father of three, a husband, a brother, a son and son-in-law, and a friend and neighbor, I get pulled in a lot of directions. In all honesty, reloading and shooting has become a stress relief for me even though I work in the shooting industry.
Sometimes, the shooting gets put on hold for other more important things but there will always be another project or repair to accomplish. There are a lot out there that have found a way to balance the work life, the family life, and the play life. I would like to applaud you on your efforts because it is a hard thing to accomplish.
Remember to take time and relieve that stress. Do something fun, especially if it is shooting that special hand-load you just made.
AccurateShooter Comment — Hand-Loading and the Creative Process
Reloading your own precise ammo can be rewarding in many ways. First it allows you a temporary escape from work pressures, “Honey-Dos”, filing your taxes — whatever. It’s just you and Mr. Rockchucker spending quality time in the loading room. Second, hand-loading is a creative process that engages the mind. During load development, you are like an inventor, selecting a powder charge, choosing the bushing size, experimenting with seating depths, working to perfect your load.
Lastly, the process of hand-loading is rewarding because you are building something start to finish. You begin with components — bullets, brass, and powder, and end up with a finished product that (hopefully) is better than the best factory ammo you could buy. It is enormously satisfying to start with piles of bullets and brass and end up with beautiful hand-loads that can deliver great accuracy.
At the request of our readers, we provide select “Deals of the Week”. Every Sunday afternoon or Monday morning we offer our Best Bargain selections. Here are some of the best deals on firearms, hardware, reloading components, optics, and shooting accessories. Be aware that sale prices are subject to change, and once clearance inventory is sold, it’s gone for good. You snooze you lose.
NOTE: All listed products are for sale to persons 18 years of age or older. No products are intended for use by minors.
Midsouth — Big Savings on Lyman Products
⏺️ » Major discounts on hundreds of Lyman products
Lookin’ for a great deal? Currently there are over 500 discounted items in the Creedmoor Sports Sale section with 90+ in the Bargain Bunker (with major price cuts). You’ll find some great savings on Sightron Scopes, Wilson and Redding presses, Edgewood Bags, Protektor Front Rests, Wilson and Redding Dies, Berger Bullets, Starline Brass and much more.
Graf & Sons — Dillon Getting Started Reloading Kit, $719.95
⏺️ » Great starter kit with BL550 press, dies, powder funnel die and more
If you’re looking to upgrade to a progressive press consider the Dillon Precision BL550 Get Started Kit. This combo features the BL550 progressive press with multiple die slots and a quick-change toolhead for fast caliber swaps. NOTE: This Dillon BL550 is upgradeable to the RL550 for higher output. This “Get Started” kit also includes a 3-die set, digital scale, powder trickler, calipers, case gauge, ammo box, and more. The kit is on sale for $719.95 for a variety of popular cartridge types including .223 Rem, .308 Win, 9mm Luger, .38 SPL, .357 Mag, .44 Mag, and .45 ACP.
Whidden Gunworks — 50% Off Rimfire Gun Ammo Testing
⏺️ » Save 50% on test to find best ammo for your rimfire gun
Whidden Gunworks is offering 50% OFF Rimfire Test Range fees. The Whidden test center team will test your .22 LR rifle or handgun at 50m and 100m with top quality ammunition from ELEY, Lapua, Norma, and RWS. Multiple lots can be tested, and then you can buy the lots that shoot best in your firearm. Whidden Gunworks even offers door-to-door valet shipping. Offer good through May 17, 2026.
As an Amazon affiliate, this site can earn revenues through sales commissions.
Whidden Gunworks makes great sizing and seating dies. The Whidden full-length sizing die with neck bushing is very popular because it allows you to “tune” the neck tension by using different bushings, with larger or smaller inside diameters. In this video, John Whidden explains how to choose a the right bushing size for use with your neck-sizing and full-length sizing bushing dies.
For most applications, John suggest starting with the caliper-measured outside diameter of a loaded cartridge (with your choice of bullet), and then SUBTRACT about three thousandths. For example, if your loaded round mics at .333, then you would want to start with a 0.330 neck bushing. John notes, however, that you may want to experiment with bushings, going down a thousandth and up a thousandth. With thin In addition, as your brass ages and the necks harden, you may want to change your bushing size.
Quick Tip: Try Flipping Your Bushings
You may also want to experiment with “flipping” your neck bushings to alternate the side that first contacts the neck of the case. (One side of the bushing is usually marked with the size, while the other side is unmarked.) So try “number side up” as well as “number side down”.
Some folks believe that one side of the bushing may allow a smoother entry, and that this can enhance concentricity. Other people think they can get very slightly more or less neck tension depending on how the bushing is oriented. This is a subtle effect, but it costs nothing to experiment.
If one bushing orientation proves better you can mark the “up” side with nail polish so that you can always orient the bushing optimally. NOTE: We have confirmed that some bushings are actually made with a slight taper. In addition, bushings may get distorted slightly when the brand name and size is stamped. Therefore there IS a reason to try both orientations.
With spring soon changing to summer, we are in peak varmint season in many parts of the country. In an area with a high number of critters, a semi-auto varmint rifle is a good choice. You get quick follow-up shots, with reliable 20-rd and 30-rd magazines.
For this Saturday at the Movies Showcase we feature a variety of semi-auto, AR-platform rifles chambered for efficient, high-velocity varmint ammo. Cartridges include: .17 WSM, .17 Remington, .20 Practical, .204 Ruger, .22 Grendel, .223 Rem, and 6mm ARC. We conclude with a video that reviews a variety of lead-free .223 Rem ammo types.
Rock Chuck Hunting in Eastern Oregon
This video has some great backcountry footage. The host nails a number of rockchucks with his .223 Rem-chambered AR-15. The shooter says that the default AR-15 cartridge works great for varmints: “The .223 Remington becomes a rockchuck hunter’s friend with the right load: Nosler 40gr Ballistic Tip loaded over a stuffed case of H335 powder. This achieves 3800 FPS with excellent accuracy.”
.17 Remington AR-15 — Small Bullet, Ultra-High Velocity
The .17 Remington wildcat is based on the .223 Remington case necked down to .172″, with the shoulder moved back. High muzzle velocity (4000+ FPS), flat trajectory, and very low recoil are the .17 Remington’s primary attributes. It has a maximum effective range of about 440 yards on prairie dog-sized animals, but the low BCs of the small .17-cal bullets makes them quite susceptible to crosswinds at such distances.
This Varminter.com video was created in spring 2022, just in time for Rockchuck and Thermal Coyote hunts. The host noted: “This was my first experience with the .17 Remington, but I was not unaware of its history and steady popularity among varmint and predator hunters. Although finding an available and affordable .17 Remington bolt-action rifle is nearly impossible nowadays, building one in an AR-15 was simple and straight-forward.” The video has full description of all the components for the build. The .17 Rem is fast — the 25gr bullet runs 3777 FPS from an 18″ barrel (see 01:42 time-mark). READ Full Story.
.17 WSM Rimfire in Franklin Armory F17-L
What’s the ultimate rimfire varmint rifle? An AR chambered for the .17 WSM could be the answer. Eric Mayer of Varminter.com states: “The Franklin Armory F17-L in .17 Winchester Super Magnum (WSM) has a lot of firsts. It is the first semi-automatic rifle in .17 WSM now available to the general public. It is the first gas-piston system, AR-15 rimfire rifle built in partnership between Franklin Armory and Osprey Defense.”
Eric has used the .17 WSM AR shooting ground squirrels, rock squirrels, prairie dogs, and rabbits. Eric notes: “The report of the .17 WSM is nowhere near as loud as most of the centerfire [varmint] cartridges. I found that when I shot the FA-17, it did not cause the other ground squirrels… to run for cover. The lack of recoil … allowed me to see right where I hit [and] if I happened to miss, [low recoil] made for quick corrections for wind, or distance.” READ Full Report
The .17 WSM is a much larger, more powerful round than the .17 HMR. See the size difference above.
Eric Mayer created his own custom .17 WSM AR-15 varmint rifle, built with a Franklin Armory F17-V4 Upper, Aero Precision Lower, and Magpul stock. This was used in California and Arizona. READ Full Story.
.20 Practical — Fast, Accurate, Easy to Form
The .20 Practical cartridge is simply a .223 Rem necked down to .20 caliber. This is a great choice for prairie dogs — and probably our favorite wildcat for the AR-15. Just neck down your .223 Rem brass, fit a .20-Cal barrel and you’re good to go. Robert Whitley notes the the .20 Practical “is a perfect cartridge for varmint hunting and general shooting — very accurate and fast! It functions 100% out of an AR-15.”
The .20 Practical offers some notable advantages for high-volume varmint shooters. The .20 Practical delivers very high velocity with very low recoil while still providing outstanding accuracy. The .20 Practical is great option for folks who favor “fast and light” — smaller, lower-mass bullets traveling at very high velocities. This little cartridge can launch 40-grainers at over 3900 FPS, and 32-grainers even faster. This makes the .20 Practical a great choice for an AR-based varmint rifle.
.20 Practical Ultimate AR Varminter
A decade ago AccurateShooter.com created a .20 Practical AR15 Ultimate Varminter with a custom 20-caliber upper from Robert Whitley of AR-X Enterprises, LLC. That project rifle was ultra-accurate — every 5-shot group out of the gun was less than the size of a dime. That gun was auctioned off, but Robert Whitley continues to produce custom 20 Practical AR-15 uppers.
You make .20 Practical cases by simply necking down .223 Rem brass to .20 caliber. You can start with standard .223 Rem brass and even load with standard .223 Rem dies. Just swap in a smaller expander and use smaller neck bushings.
Prairie Dog Hunt with .204 Ruger AR — Watch The P-Dogs Fly
The video was created during a 2018 prairie dog safari. It has stunning footage of hits on P-Dogs at multiple distances. You can see over FIFTY hits with some amazing P-Dog aerials. Watch the first flyin’ dog at 00:20 time-mark and there’s a truly spectacular gut-busting hit at 3:13. That shows the potency of a high-speed .20-cal projectile. The shooter was using a custom-built AR-15 chambered in a .204 Ruger. That cartridge was driving 35gr Berger hollow point bullets at a stunning 4050 FPS! The rifle was fitted with a Dakota silencer suppressor and many other custom components. If you’ve never tried prairie dog hunting, watch this video start to finish and you may be hooked.
6mm ARC AR-15 Varmint Rig
This Varminter.com video examines the 6mm ARC cartridge from a varmint hunter’s perspective. Created by Hornady, the 6mm ARC was designed for target shooting and medium-sized game both in bolt guns and Modern Sporting Rifles. Hornady states: “The 6mm ARC … fits in an AR-15-pattern action, functions reliably out of standard-capacity 24- or 17-round magazines. It delivers substantially better ballistics than the .223 Rem[.]” This video examines how the 6mm ARC performs in an AR-15 for varmint and predator hunting. The host reviews available factory varmint loads. The video also examines reloading components for the 6mm ARC — brass and bullets. CLICK HERE for full article.
Cottontail Rabbit Hunting with Suppressed .204 Ruger AR-15
As a varmint hunting tool, the .204 Ruger in an AR-15 is a versatile, worthy cartridge/rifle combo for the job. This video covers a cottontail rabbit hunt. The host states that “We were contacted by a farmer who was being slammed with cottontail rabbits eating out huge portions of his alfalfa fields.” This suppressed .204 Ruger AR-15 proved seriously effective on the rabbits, driving high-velocity rounds with impressive accuracy. See more details on the Varminter.com website.
The .22 Grendel is an extremely accurate and efficient cartridge based on the 6.5 Grendel necked down to .22 caliber. The case can drive 55gr varmint bullets at high velocities — over 3500 FPS. With a faster-twist barrel you can load up to 90gr bullets at 2500 FPS. The tester achieved velocities close to a 22-250. The short, fat case fits in AR-15 magazines, but may not feed as reliably during rapid fire. The tester did experience one double-feed.
Lead-Free Ammo Offerings Tested in .223 Rem AR-15
Some states — such as California — prohibit hunting with bullets that contain lead. If you plan to hunt in an area with such restrictions, you’ll need to find a lead-free substitute. Thankfully a number of manufacturers produce ammo with solid brass projectiles or other lead-free bullet designs. This Varminter.com video reviews .223 Remington no-lead ammunition from Cor-Bon, Hornady, Nosler and Winchester. These ammo types were tested in a AR-15 varmint rifle, used in a coyote hunt featured at the end of the video. SEE Full Story on Varminter.com.
The RCBS Lock-Out Die can also be used with some Dillon and Hornady progressive presses.
If you load pistol or rifle ammo with a progressive press, we strongly recommend you get a Lock-Out Die from RCBS. This unique reloading die will prevent your progressive press from advancing if the dispensed powder charge is more or less than about 0.3 grains too high or too low. The Lock-Out Die really works. Your Editor uses it on his RCBS 2000 progressive press. I can affirm that a Lock-Out Die has “saved my bacon” a half-dozen times over the years when there was an over-charge (which could cause a Kaboom) or a low charge (which could cause a squib load).
The Lock-Out Die works by using a central die detection rod that sets its vertical position based on the height of the powder column in the case. Through an ingenious design, if the powder column height is too low or too high, the rod locks in place as you start to pull the press handle. This halts the press before the ram can lift and the cartridge plate can advance. Unlike a beeping alarm system (which can be ignored or defeated), the Lock-Out Die physically stops the movement of the press ram and prevents a bullet being seated in the “problem” case.
It takes a bit of tweaking to get the Lock-Out Die detection rod setting just right, but once it is correctly positioned, the Lock-Out Die works smoothly in the background. The Lock-Out Die won’t interfere with the loading process unless it detects a high or low charge — and then it positively stops the progressive loading cycle.
While crafted for use in RCBS progressive presses, the RCBS Lock-Out Die can also be used on a Dillon XL Progressive (see video below) or Hornady Lock-N-Load progressive — though it does take up one station which could otherwise be used for a final crimp die (after the seating die). The RCBS 2000 has one more station than a Dillon 550/650, so it’s an ideal platform for using the Lock-Out Die.
Learn More at UltimateReloader.com
On the UltimateReloader.com website, run by our friend Gavin Gear, you’ll find an excellent two-part series on the function and set-up of the RCBS Lock-Out Die. Part One explains how the Lock-Out Die functions, using cut-away illustrations. Part Two shows how to install and adjust the Lock-Out Die on various progressive presses. The Ultimate Reloader video at the top of this article shows setup of the RCBS Lock-Out Die on the Dillon XL-650 progressive press, while the Reloading Bench video below shows the Lock-Out Die on a Hornady LnL progressive.
Close-up view of a sectioned case. This one here was “fixin’ to pop”, observed Glen Zediker.
Here are highlights from an article Glen Zediker wrote for the Midsouth Blog. In that article Glen, who sadly passed away in 2020, focused on cartridge brass. Glen identified the most common failures that appear with brass that has been shot multiple times, or which has been fired at excessive pressures. Glen explained some simple ways to check your cartridge brass to detect “early warning signs” of case failure, particularly case head separation, which can be very dangerous.
How Cases Degrade with Multiple Firings By Glen Zediker
This article explains when, and then how, to check after the progress of changes commencing with the firing on a new case. It’s the “progress of degeneration,” in a way of looking at it because the concern is getting a handle on when enough change in the brass has come about to require attention. Or abandonment. As said then, for me that’s 4 firings. That, as said last time, is when I might see changes that need attention. Also as said, that figure didn’t come out of a hat, but from my own notes in running my competition NRA High Power Rifle loads. [Editor’s Note: With Lapua brass, using moderate loads, in bolt-action rifles, we typically get about 10 good (match-worthy) firings. But if you anneal your Lapua brass, and run modest pressures, Lapua brass can perform well for 20 or more load cycles.]
The areas most affected are the case neck and case head area. Case neck walls get thicker [but] the case head area body walls get thinner. Primer pockets get shallower and larger diameter.
This case shows a cracked neck AND a crack (separation) above the case head. Zediker says it is “rare to see one case with both of the most common failures. [This case] was attacked by an M14.”
Case Head — Causes of Separation and Cracking
When a case is under pressure during firing, the brass, like water, flows where it can, where it’s more free to move. Of course, the chamber steel limits the amount it can expand. The case shoulder blows fully forward and the case base is slammed back against the bolt face. There is, therefore and in effect, a tug on both ends — it gets stretched. The shoulder area is relatively free to expand to conform to the chamber, but the other end, the case head area, is not. Since that’s the area of the case with the thickest walls, it doesn’t expand “out” much at all. What it does is stretch. The “case head area,” as I refer to it here, is the portion of the case above the web, which is just above the taper that leads in to the extractor groove. The “area” extends approximately an eighth-inch up the case body.
Here’s a “pressure ring.” You’ll see this after firing, if you see it. And, if you see it, that case is done. The bright ring indicates excessive stretching, which indicates excessive thinning. If you see a ring circling the case, noticeable because it’s lighter color than the case body, and it’s in this area, I’d say that case is done. And that’s right where a “head separation” occurs. It can crack and also blow slap in two, and that’s the “separation” part of case head separation.
Photo courtesy GS Arizona.
This is a spot to keep close watch on as cases age. It is also the area that is more “protected” by sizing with less case shoulder set-back. That is, pretty much, where the freedom for the stretching movement in this area comes from (the case shoulder creates a gap). If you’re seeing a sign that a head separation [might happen with relatively few firings], chances are the shoulder set-back is excessive, and also… the load pressure level.
Bent Paper Clip Case-Wall Gauge
Editor: 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.” Photo by GS Arizona.
Monitor Primer Pocket Dimensional Changes
Another case-head-area and pressure-related check is the primer pocket. As said, the primer pocket will get larger in diameter and shallower in depth each firing. As with many such things, the questions are “when” and “how much,” and the main thing, “how much?”
If the pocket gets excessively shallow, and that’s judged by a primer that seats fully but isn’t at least a tick below flush with the case base, there could be function issues. There’s a risk of a “slam-fire” with a semi-auto that uses a floating firing pin, and, if there is actual protrusion, that has the same effect as insufficient headspace. A primer pocket uniformer can reset the depth of a shallowed primer pocket to what it should be, but the real test for me is how easily the next primer seats into it. If it’s significantly less resistance, I’ll say that case is done. Shallower can be refurbished. That’s a primary function of a primer pocket uniformer. Larger diameter, though, can’t be fixed. I’ve mentioned in another article or two that, any more at least, my main gauge of load pressure has become how much primer pocket expansion there’s been.