The U.S. Army Marksmanship Unit (USAMU) published a series of reloading articles on its Facebook Page. In this article, the second in a 3-part series, the USAMU covers the process of loading competition pistol ammunition. The authors focus on two key elements — the taper crimp and the quality/uniformity of the original brass. If you shoot pistol competitively, or just want to maximize the accuracy of your handguns, read this article. The taper crimp tips are very important.
Loading Accurate Competition Pistol Ammunition — Part 2 of 3
Today, we resume our series on factors affecting accuracy in pistol handloads. Readers who missed Part One can visit our USAMU Facebook Page. Scroll down to March 28, 2018 to find that first installment which is worth reading.
One often-overlooked aspect of handloading highly-accurate pistol ammunition is the amount of taper crimp used, and its effect on accuracy. (NOTE: this article pertains to loading for semi-autos – revolver crimp techniques involve some quite different issues.) Briefly, different amounts of taper crimp are used with various handloads to obtain best accuracy. The amount is based on bullet weight, powder burn rate and charge, plus other factors such as case neck tension. During machine-rest testing of experimental Service Pistol ammunition, many variables are examined. Among these, our Shop often varies a load’s crimp in degrees of 0.001″ when re-testing for finest accuracy.
How to Measure Taper Crimp on Pistol Cartridges
One question that often arises is, “How do I measure the taper crimp I’m putting on my cartridges?” Using the narrow part of one’s dial caliper jaws, carefully measure the case diameter at the exact edge of the case mouth on a loaded cartridge. It’s important to take several measurements to ensure consistency. Also, be sure to measure at several places around the case mouth, as case wall thickness can vary. After measuring 2-3 cartridges with a given crimp setting, one can be confident of the true dimension and that it can be repeated later, if needed.
However, for good results, one must use brass from one maker due to variances in case wall thickness. For example, the same degree of crimp that imparts a measurement of 0.471″ with Brand X brass may result in 0.469″ with Brand Y. Thus, for best accuracy, using brass from the same manufacturer is important — particularly for 50-yard Slow Fire. In a perfect world, it is better still to use brass from one lot number if possible. With the popularity of progressive presses using interchangeable tool heads, keeping separate tool heads adjusted for each load helps maximize uniformity between ammunition lots.
Brass Uniformity and Accuracy
Brass is important to pistol accuracy. While accurate ammunition can be loaded using brass of mixed parentage, that is not conducive to finest results, particularly at 50 yards. It is important for the serious competitor to pay attention to his brass – even if only for the 50-yard “Slow Fire” portions of “Bullseye” matches and practice. By segregating brass as described above, and additionally keeping track of the number of times a given batch of cases has been fired, one can ensure case neck tension and case length are at their most uniform.
Given the large volumes of ammunition consumed by active pistol competitors, using inexpensive, mixed surplus brass for practice, particularly at the “short line” (25 yards), is understandable. In NRA Outdoor Pistol (“Bullseye”), the 10-ring is relatively generous — especially for a well-trained shooter with an accurate pistol and load. However, for the “long line” (50 yards), purchasing and segregating a lot of high-quality brass to be used strictly for slow-fire is a wise idea. To keep track of your brass on the line, use a unique headstamp marking with 1 or 2 colors of marking pen ink.
Uniform Cartridge Overall Length is Important
Cartridge case Overall Length (OAL) uniformity as it comes from the factory is important to achieving utmost accuracy. More uniform case lengths (best measured after sizing) contribute to greater consistency of crimp, neck tension, ignition/burn of powder charge, headspace (rimless cartridges), etc. Cartridge case-length consistency varies noticeably by maker and, with lesser manufacturers, also from lot to lot. Some manufacturers are more consistent in their dimensions than others, and also in the hardness/ductility of their brass. Similarly, pay attention to primer brands, powder lot numbers, etc.
Consider Using a Lock-Out Die with Progressive Presses
When reloading pistol ammo with a Progressive press, we strongly recommend the use of a lock-out die, or other system that can detect double charges or low charges. If your progressive is manually advanced, the possibility of a double charge is very real — and that can have disastrous consequences.
On UltimateReloader.com website you’ll find an excellent two-part series on the function and set-up of the RCBS Lock-Out Die. This die prevents loading if a high or low powder charge is detected. The video above shows setup of the RCBS Lock-Out Die on the Dillon XL-650 progressive press.
Gunsmith Darrell Holland sells a Priming Tool Adapter that upgrades the RCBS Auto Bench Priming Tool with key features — including primer seating depth control. If your hand starts to hurt after priming dozens of cases with a hand-held, squeeze-type priming tool, you may want to consider Holland’s invention, which he calls the “Perfect Primer Seater” (PPS).
Holland basically has modified the RCBS lever, adding a precise crush control and a means of measuring depth with a gauge. He claims this gives “an EXACT primer seating depth based on primer pocket depth and primer thickness”. With Holland’s PPS, primer seating depth is controlled with a rotating wheel that limits lever travel in precise gradations. You can buy the complete priming system for $340.00, or, if you already own the RCBS Auto Prime tool, you can purchase an adapter kit (with base, arm, adjuster, and gauge etc.) for $190.00. To order, visit Hollandguns.com Reloading Equipment Page. Look for the Perfect Primer Seater Adapter for $190.00 or order the Complete Unit for $340.00.
User Review by Tommy Todd
Sierra Bullets’ Chief Ballistician Tommy Todd acquired the Holland Perfect Primer Seater, and gave it a positive review. Todd writes: “This cartridge case priming system allows you to measure the primer pocket depth and adjust the seating tool to match the primer seating depth for a contact fit with a measured lot of primers to the cases you are working with. Mr. Darrell Holland has taken a standard RCBS automatic bench-mounted priming tool and modified it to a new level of precision. The modifications allow you to measure the primer pocket depth, primer height, and with the addition of an adjustable stop on the priming tool achieve precision primer seating, rather than how the primer ‘feels'[.]
If you are already utilizing the RCBS priming tool, Mr. Holland offers an adapter kit to upgrade your equipment. If you are looking for a new priming unit, I suggest giving this product a try. Increasing consistency when seating primers should result in smaller groups[.]”
The 17th Edition of the Cartridges of the World was released in June, 2022, so it is still quite current. This massive 704-page reference contains illustrations and load data for over 1500 cartridge types. That makes it a unique, very valuable resource. If you shoot a wide variety of cartridges, or are a cartridge collector, this book is a “must-have” resource. The latest 17th Edition includes 30+ new cartridge types and 1500+ photos. The print version costs $32.97 at Amazon.com plus $3.99 shipping. Or you can get the print book from Amazon 3rd party sellers starting at $27.38 delivered plus $3.99 shipping. The Kindle eBook version costs $19.47.
Updated 17th Edition with Feature Articles
The 17th Edition of Cartridges of the World includes cartridge specs, plus tech articles on Cartridge identification, SAAMI guidelines, wildcatting, and new cartridge design trends. Cartridges of the World, the most complete cartridge reference guide in print, includes a full-color section with feature articles such Cartridges of the AR-15, Creedmoor Cartridge Family, .404 Jeffrey, .30 Carbine, plus “Cartridges and Cans” (suppressors).
View Free Book Sample Content
FREE STUFF for You: If you want to see what you are getting, there is a very large sample section of the previous 16th Edition available online with over 100 pages of content and dozens of photos and illustrations. To access all this FREE INFO, CLICK HERE, then click on the cover photo where it says “Look Inside”.
NOTE: This is content from the 16th Edition, but most is the same in the 17th Edition.
Cartridges of the World 17th Ed. CHAPTERS:
Chapter 1: Current American Sporting Cartridges
Chapter 2: Obsolete American Rifle Cartridges
Chapter 3: Wildcat Cartridges
Chapter 4: Proprietary Cartridges
Chapter 5: Handgun Cartridges of the World
Chapter 6: Military Rifle Cartridges of the World
Chapter 7: British Sporting Rifle Cartridges
Chapter 8: European Sporting Rifle Cartridges
Chapter 9: American Rimfire Cartridges
Chapter 10: Shotgun Shells
Chapter 11: U.S. Military Ammunition
Chapter 12: Cartridge ID by Measurement
Need something for the walls of your “man cave” or reloading room? Looking for a great birthday gift for one of your shooting buddies? The creators of the Cartridge Comparison Guide offer a collection of wall posters showing ammunition types from 17 caliber rimfire cartridges all the way up to giant 35mm military rounds. ChamberIt.com currently offers 12 different large wall posters that display a huge variety of cartridge types. For example, the American Standard Poster (shown above) contains every standardized cartridge mass produced in the USA as of 2021. The cartridges are 100% to scale (life size). These posters feature full color images on high gloss / high quality 100-lb poster paper.
For example, the Rifleman’s Classic Poster (below), a full 38 inches wide and 27 inches tall, is the most comprehensive. This $17.76 poster displays over 300 rifle cartridge types at true size (within 4/1000 of an inch). Cartridges shown range from .17 caliber all the way up to the big boomers (including some cannon shells). The Rifleman’s Classic Poster includes nearly all American Standardized Rifle Cartridges and many European rifle cartridges.
Rifleman’s Classic Poster Click to view large size poster.
Ammunition Performance Specifications Poster
There is also an interesting Ammo Performance Specs poster. This shows dozens of popular hunting cartridges with the velocity, energy, momentum and recoil for each cartridge displayed in a bar graph.
This shows the actual size of the Ammo Performance Poster as displayed on a wall.
For today’s Sunday GunDay story, we feature highlights from two in-depth reports on rifles built around the relatively new 6GT cartridge (also known as the “6mm GT”). Developed by George Gardner (G.A. Precision) and Tom Jacobs (Vapor Trail), the 6GT was designed to feed well from magazines, be more efficient than the 6mm Creedmoor, and offer outstanding accuracy. It is just enough bigger than the 6mmBR or 6 Dasher so it feeds better. But it retains many of the qualities of the 6mmBR (high efficiency and outstanding accuracy). Burning significantly less powder than the 6mm Creedmoor, the 6GT is a bit less expensive to shoot, and should, theoretically at least, deliver better barrel life.
“The [6GT] is a more predictable and barrel-friendly cartridge than the 6mm Creedmoor. It can utilize the accurate and forgiving powders of the 6BR, has fantastic accuracy, and due to its shoulder angle and case length, it doesn’t suffer from feeding issues.” — PewPewTactical.com
We should say that the 6 Dasher has been used very successfully in PRS/NRL competition, with some aftermarket magazine accessories. For this reason, if you already shoot a 6 Dasher, moving to a 6GT may not be worth the cost of new dies and new brass. A.J. Deysel, writing for LoadDevelopment.com, writes:
“The longer case of the 6mm GT means it feeds as reliably from a magazine as a 6mm Creedmoor, and offers slightly higher powder capacity and in turn velocities than the 6mmBR variants, whilst still being able to use the same accurate and forgiving propellants.
You will also find many competitive and average Joes shooting 6mmBR and 6mm Dashers with a Primal Rights or some other mag conversion kit, having very few if any mag-feed issues at all, so that pretty much also nullifies the need to move away from those [chamberings] if you already own one of those or the reloading equipment for it.” — LoadDevelopment.com
Part I: The 6GT Cartridge for Precision Rifle Competition
Report by Vu Pham
I was ready to build a 6 Dasher when I saw a lot of buzz… about a new caliber George Gardner (Owner of G.A. Precision) and Tom Jacobs (Owner of Vapor Trail Bullets) designed, the 6GT. After some research and talking to George, I ditched the 6mm Dasher build and had GA Precision build me a 6GT on a GAP Templar action I already had in the safe. The reasons to try the 6GT in a new PRS-style rig were as follows:
1. Push a 110-115 grain class bullet at 2880-2930 FPS safely in the Sacramento heat.
2. Achieve a load that is reliable and predictable. The caliber must be easy-to-tune and predictable from barrel to barrel. I don’t want to spend weeks developing a new load each time I spin on a fresh barrel.
3. Be able to run the same mag in all my guns without having to tweak or use mag kits. The round must feed from AICS and AW magazines without major tweaking or hiccups.
4. Get good barrel life. The barrel needs to go 2200-2500 rounds with match-grade reliability and accuracy.
5. Have a competitive cartridge with the least possible recoil without sacrificing too much performance down range, compared to bigger options like the 6mm Creedmoor.
6GT feeding from un-modified magazines has been flawless in all the rifles we tested. The 6GT feeds so well, I sometimes have to do a press check to ensure there is a round in the chamber.
On paper the 6GT seemed like the perfect cartridge for PRS- and NRL-style competition. It has the low recoil of a 6 Dasher, with good feeding and mag compatibility. With the 6GT, a competitor can push 105gr bullets at 3000+ FPS or run heavier bullets at 2800-2900+ FPS.
Knowing that I would initially have to make my own 6GT brass and do quite a bit of load development, I enlisted the help of Dan Bertocchini with CS Tactical. Dan has a lot more experience with wildcats and is the man when it comes to this type of data gathering. He has been running a 6 Dasher for a few years so I was curious how he would compare the 6GT to his 6 Dasher.
Quick Summary: “I am really digging the 6GT and the capabilities it offers. It can launch 103gr Vapor Trails at 3000+ FPS or lob heavy 115gr DTACs in the low-to-mid 2900s comfortably. I think we will see this cartridge go mainstream in PRS/NRL-style competition in 2020.” — Vu Pham
The new 6GT Cartridge Was Tested in Three (3) Tactical Rifles:
Rifle 1: Vu’s 6GT 1.0
Builder: GA Precision
Action: Left Hand GAP Templar (large firing pin)
Barrel: Bartlein 7.7 Twist finished at 26″ with a 419 Hellfire Brake
Stock: KMW Sentinel
Optic: Vortex Razor Gen II 4.5-27x56mm EBR-7C MRAD
Bi-Pod: Harris
Trigger: Timney Calvin Elite
Magazines: AICS and AW
Support Bag: Wiebad Fortune Cookie
Rifle 2: Vu’s 6GT 2.0
Builder: Rubicon Precision
Action: Impact Precision 737
Barrel: Bartlein 7.0 Twist finished at 27″ with a 419 Hellfire Brake
Stock: XLR Industries Envy Chassis
Optic: Vortex Razor Gen II 4.5-27x56mm EBR-7C MRAD
Bi-Pod: Harris with Henderson Arca adapter
Trigger: Trigger Tech Diamond
Magazines: AICS and AW
Support Bag: Wiebad Fortune Cookie
Rifle 3: Dan’s 6GT
Builder: CS Tactical
Chambered by: Rubicon Precision
Action: Lone Peak Arms Fusion
Barrel: Proof 7.0 Twist finished at 28″ with a Muzzle Brake and More Brake
Stock: XLR Industries Envy Chassis
Optic: Minox ZP5 5-25x56mm MR4
Bi-Pod: Arca Cyke Pod (PRS)
Trigger: Trigger Tech Diamond
Magazines: MDT
Support Bag: Armageddon Gear OG Game Changer, Waxed Canvas
Alpha Munitions Pre-Production 6GT Brass George Gardner was kind enough to send us 50 pieces of Pre-Production Alpha 6GT brass for preliminary testing. Like the cases I formed from 6.5×47 Lapua brass, the Alpha 6GT brass will use a small rifle primer. Purchased direct from Alpha Munitions, 6GT brass is now $1.30 per case, which is comparable with Lapua 6mm Creedmoor brass, currently $120.99/100 at Grafs.com.
The major difference between 6.5×47 Lapua-formed brass and Alpha 6GT brass is the case capacity. Alpha 6GT brass has 1.5 to 1.7 grains more case capacity. When a piece of 6.5×47 Lapua brass is formed into a 6GT, the walls of the case now become the shoulder and part of the neck. In a normal piece of brass, the shoulder and neck are typically thinner because of the thickness of the brass tapering from the body to neck.
While the cartridge design was optimized for Hodgdon Varget, the extra case capacity of the Alpha 6GT brass opens the door to Hodgdon H4350 (my favorite powder) and Alliant Reloder 16.
Test Results with Alpha Munitions 6GT Brass
Initial test results were as expected from a premium brass-maker. Dan and I both got excellent Standard Deviations and Extreme Spreads over my MagnetoSpeed V3 and his LabRadar. This string below was with 112gr Barnes Match Burners and 33.8 grains of Varget. Can’t complain about a 3 FPS Extreme Spread!
Yes, H4350 Works with the Alpha Munitions Brass
Personally, I prefer running Alpha 6GT brass with H4350 rather than Varget pushing a heavier bullet. H4350 burns slower and cleaner which should equate to better barrel life. The Lapua-formed 6GT cases just do not have the capacity to reach the cartridge’s full capability with the slower burning powders.
Is the 6GT cartridge accurate? Definitely. Here is a 5-shot group at 600 yards shot by Dan. This was Alpha 6GT brass, with Hodgdon H4350 pushing Barnes 112gr Match Burner bullets.
PART II — 6GT Load Development with Multiple Powders
This text is taken from a full report by Mike McCasland on his 6GT (aka “6mm GT”) bolt action rifle. This rig was designed for general use, not just for PRS/NRL matches. In his 6GT rifle, Mike tested multiple powders including Varget, H4350, Reloder 16, Reloder 15, Shooters World Precision, and Vihtavuori N140. For more details, CLICK HERE for full report.
About the 6mm GT Cartridge
BRASS — The first thing you’ll find is cartridge brass choices for the 6 GT are rather limited currently. At present, the only commercial options are Hornady and Alpha Munitions. For the die-hard Lapua fans, you can technically make 6mm GT brass from 6.5×47 Lapua, however that process is very labor-intensive.
I have used both Hornady and Alpha brass in this rifle and haven’t noticed much difference between the two. I will say that my batch of Alpha brass was slightly softer than Alpha brass I’ve used in other calibers; you could feel a difference when neck turning cases. I’m unsure if that’s a batch issue, or something specific to their 6mm GT brass as a whole. As far as performance, there was little discernable difference. Oddly enough, the Hornady brass seemed to have slightly less case capacity than the Alpha; with most other cartridges it’s the other way around.
POWDERS — The 6mm GT was designed with Hodgdon Varget in mind, and that popular powder works exceedingly well in this platform. That said, the 6mm GT can work with a wide variety of powders, some yielding better performance than Varget.
I’ve tried a multitude of powders during my initial 6mm GT load development: Varget, Shooters World Precision, RL16, VV N140, H4350, and RL-15 to name a few. In my barrel, Hodgdon H4350 seems to deliver the best velocity/accuracy combination. SD and ES also seemed to be the lowest with H4350.
Load Development for the 6mm GT — Many Powders Tested
BULLETS — The most common 0.120″ freebore chamber allows for the majority of high-BC 6mm projectiles found in both F-Class and PRS. I had good luck with the pointed 107gr Sierra Match Kings (SMK), as well as the 110gr Hornady A-Tips in my rifle. For those looking to run the heavier 112-115 grain 6mm offerings, I believe GAP designed a 0.160″ freebore reamer that gets those bullets out of the neck/shoulder junction. Shown below is the 0.120″ freebore JGS reamer print:
SUMMARY — Good Cartridge with Much Potential
Generally speaking, I think the 6mm GT is a good little round. Some may not subscribe to this theory, but I believe some cartridges are inherently easier to tune than others. I’m not sure the 6mm GT is as easy-to-tune as a 6mmBR, 6 Dasher, or 6 BRA, but I don’t think it lags that far behind.
With relatively little trouble, I was able to find loads with both Varget and H4350 that would consistently shoot very well — 0.2 to 0.3 MOA. Moreover, I found the 6GT cartridge lives up to the velocity claims made by G.A. Precision. I was easily able to push the 110gr A-Tips to 2950 FPS, and the 107gr SMKs to low 3000 FPS range without any pressure signs, or unnecessary wear and tear on the brass.
As a fun test, I ran my 6mm GT rifle in a local 1000-yard F-Class match with the 110gr A-Tips, just to see just how well they would perform. Although wind conditions of the day and some E-Target issues prevented my 6mm GT rig from getting the better of the larger 7mm and .30-Cal rifles, the 6mm GT proved itself an accurate little round at distance. Here is a 1000-yard ShotMarker target:
After putting several hundred rounds through my 6mm GT rifle, I anticipate building another 6GT on a repeater action to give PRS a try. I think if you are looking for a dual-purpose rifle that can run tactical matches (with 100% feeding reliability), and can also be used for mid-range, F-Open Class competition, the 6mm GT would be a very good option.
About the author, Mike McCasland:
Mike McCasland is an avid shooter who competes regularly in F-Class matches. Based in Texas, Mike is the creator of the Texas Precision YouTube Channel. There you’ll find many videos covering reloading, gun projects, and marksmanship. Mike has done some notable product reviews including a comparison test of Micrometer Competition Seating Dies. To access Mike’s YouTube Channel, CLICK HERE.
Have inflation (and supply chain shortages) affected the price of powder? You bet. Probably WAY more than you could imagine. Forum member “Two Time HM LR” posted this interesting photo (above) showing Hodgdon powder prices from 1978, as sold by O.K. Weber in Oregon.
Eight Pounders under $45.00 in 1978
Now the prices — $20 to $44 — may not get your attention at first. But take note that these numbers are for EIGHT pound containers. Yep eight-pounders were all under $45! For example, H4895 was $44 for 8 pounds back in 1978, 45 years ago. And H335 was $20 for eight pounds — that’s just $2.50 per pound!
These days a single pound of a desirable powder such as H4831 might cost $60+ at some stores IF you can find it at all. On Hodgdon’s web site, H4831 powder is priced at $54.99 per pound in August 2023. Using that current $54.99/lb figure, H4831 is now TEN times higher than it was in 1978, when H4831 cost $44 for 8 pounds, i.e. $5.50 per pound.
Here are some comments from our Forum Members:
“Heck those prices are just about the same as current ones, just a little smaller container now.” — Joe
“I’ve got some H4831 in a can marked ‘WWII Surplus Powder’ with a price tag of $2.75. We’ll never see that again either.” Rick in Oregon
“1978 prices and 2022 income would be nice. Unfortunately that doesn’t work. If you compare prices and income, powder cost about the same. You also have to discount the temporary gouging that we are seeing.” — Tmwinds
“So I used to buy gas for 10 cents per gallon and they’d pump it, check the oil, and clean the windshield.” — Pirate Ammo
One comment suggests that the powder price hike actually tracks general U.S. currency inflation over the last four decades. So perhaps powder price increases are not as bad as they seem, when compared to how all prices have risen since 1978:
“Using H4895 as a comparison basis at $58.50 (list price) in 1978 calculates it to $275 in todays money. Looking at Powder Valley prices it looks like around [$340 in August 2023] for the same item in todays money [a 24% increase in real dollars]. Availability is another issue though and if someone is really needing powder they may well have to pay above suggested retail.” — Drover
Put the same load in a variety of barrels (with the same length and chamberings) and you’ll see a wide variance in muzzle velocity. In fact, it’s not unusual to see up to 100 fps difference from one barrel to the next. We demonstrated this with a comparison test of Lapua factory ammo.
Chron Testing Lapua Factory Ammo
At our Southern California test range some years ago, we chronographed Lapua 105gr 6mmBR factory ammo in three different 8-twist barrels of similar length. The results were fascinating. Lapua specs this ammo at 2790 fps, based on Lapua’s testing with its own 26″ test barrel. We observed a speed variance of 67 fps based on tests with three aftermarket barrels.
Barrel Velocity Variance
Brand ‘S’ and Brand ‘PN’ were pre-fit barrels shot on Savage actions. Brand ‘K’ was fitted to a custom action. All test barrels were throated for the 100-108 grain bullets, though there may have been some slight variances in barrel freebore. With a COAL of 2.330″, the rounds were “jumping” to the rifling in all barrels.
Among the four barrels, Brand ‘PN’ was the fastest at 2824 fps average — 67 fps faster than the slowest barrel. Roughly 10 fps can be attributed to the slightly longer length (27″ vs. 26″), but otherwise this particular barrel was simply faster than the rest. (Click Here for results of 6mmBR Barrel Length Velocity Test).
IMPORTANT: Results Are Barrel-Specific, Not Brand-Specific
These tests demonstrate that the exact same load can perform very differently in different barrels. We aren’t publishing the barrel-makers’ names, because it would be wrong to assume that ‘Brand X’ is always going to be faster than ‘Brand Y’ based on test results from a single barrel. In fact, velocities can vary up to 100 fps with two identical-spec barrels from the SAME manufacturer. That’s right, you can have two 8-twist, 26″ barrels, with the same land-groove configuration and contour, from the same manufacturer, and one can be much faster than another.
Don’t Demand More Than Your Barrel Can Deliver
We often hear guys lament, “I don’t get it… how can you guys get 2900 fps with your 6BRs and I can only get 2840?” The answer may simply be that the barrel is slower than average. If you have a slow barrel, you can try using more powder, but there is a good chance it may never run as fast as an inherently fast barrel. You shouldn’t knock yourself out (and over-stress your brass) trying to duplicate the velocities someone else may be getting. You need to work within the limits of your barrel.
Factory Ammo Provides a Benchmark
If you have a .223 Rem, 6mmBR, .243 Win, 6.5×47 Lapua, 6.5 Creedmoor, 6.5×55, .308 Win, .30-06 Springfield, or .338 LM Rifle, we recommend you buy a box of Lapua factory-loaded ammo. This stuff will shoot great (typically around half-MOA), and it can give you a baseline to determine how your barrel stacks up speedwise. [Editor’s NOTE: The original test was conducted in 2008. The velocity of current-production Lapua factory ammo might be higher or lower, so your results may vary.]
When you complete a new 6mmBR rifle, it’s definitely smart to get a box of the factory ammo and chronograph it. That will immediately give you a good idea whether you have a slow, average, or fast barrel. Then you can set your velocity goals accordingly. For example, if the factory 6BR ammo runs about 2780-2790 fps in your gun, it has an average barrel. If it runs 2820+ in a 26″ barrel (or 2835 fps in a 28″), you’ve got a fast tube.
Here’a useful article by Sierra Bullets Media Relations Manager Carroll Pilant. This story, which originally appeared in the Sierra Bullets Blog, covers some of the more common ammo problems that afflict hand-loaders. Some of those issues are: excessive OAL, high primers, and improperly-sized cases. Here Mr. Pilant explains how to avoid these common problems that lead to “headaches at the range.
I had some gentlemen at my house last fall getting rifle zeros for an upcoming elk hunt. One was using one of the .300 short mags and every 3rd or 4th round would not chamber. Examination of the case showed a bulge right at the body/shoulder junction. These were new cases he had loaded for this trip. The seating die had been screwed down until it just touched the shoulder and then backed up just slightly. Some of the cases were apparently slightly longer from the base to the datum line and the shoulder was hitting inside the seating die and putting the bulge on the shoulder. I got to thinking about all the gun malfunctions that I see each week at matches and the biggest percentage stem from improper handloading techniques.
One: Check Your Cases with a Chamber Gage
Since I shoot a lot of 3-gun matches, I see a lot of AR problems which result in the shooter banging the butt stock on the ground or nearest solid object while pulling on the charging handle at the same time. I like my rifles too well to treat them that way (I cringe every time I see someone doing that). When I ask them if they ran the ammo through a chamber gage, I usually get the answer, “No, but I need to get one” or “I didn’t have time to do it” or other excuses. The few minutes it takes to check your ammo can mean the difference between a nightmare and a smooth running firearm.
A Chamber Gauge Quickly Reveals Long or Short Cases
Size Your Cases Properly
Another problem is caused sizing the case itself. If you will lube the inside of the neck, the expander ball will come out a lot easier. If you hear a squeak as the expander ball comes out of a case neck, that expander ball is trying to pull the case neck/shoulder up (sometimes several thousandths). That is enough that if you don’t put a bulge on the shoulder when seating the bullet … it can still jam into the chamber like a big cork. If the rifle is set up correctly, the gun will not go into battery and won’t fire but the round is jammed into the chamber where it won’t extract and they are back to banging it on the ground again (with a loaded round stuck in the chamber). A chamber gage would have caught this also.
Oversizing cases also causes problems because the firing pin doesn’t have the length to reach the primer solid enough to ignite it 100% of the time. When you have one that is oversized, you usually have a bunch, since you usually do several cases at a time on that die setting. If the die isn’t readjusted, the problem will continue on the next batch of cases also. They will either not fire at all or you will have a lot of misfires. In a bolt action, a lot of time the extractor will hold the case against the face of the breech enough that it will fire. The case gets driven forward and the thinner part of the brass expands, holding to the chamber wall and the thicker part of the case doesn’t expand as much and stretches back to the bolt face. If it doesn’t separate that time, it will the next time. When it does separate, it leaves the front portion of the case in the chamber and pulls the case head off. Then when it tries to chamber the next round, you have a nasty jam. Quite often range brass is the culprit of this because you never know how many times it has been fired/sized and in what firearm. Back to beating it on the ground again till you figure out that you have to get the forward part of the case out.
Just a quick tip — To extract the partial case, an oversized brush on a cleaning rod [inserted] and then pulled backward will often remove the case. The bristles when pushed forward and then pulled back act like barbs inside the case. If you have a bunch of oversized case that have been fired, I would dispose of them to keep from having future problems. There are a few tricks you can use to salvage them if they haven’t been fired though. Once again, a case gage would have helped.
Two: Double Check Your Primers
Another thing I see fairly often is a high primer, backwards primer, or no primer at all. The high primers are bad because you can have either a slam fire or a misfire from the firing pin seating the primer but using up its energy doing so. So, as a precaution to make sure my rifle ammo will work 100% of the time, I check it in a case gage, then put it in an ammo box with the primer up and when the box is full, I run my finger across all the primers to make sure they are all seated to the correct depth and you can visually check to make sure none are in backwards or missing.
Three: Check Your Overall Cartridge Length
Trying to load the ammo as long as possible can cause problems also. Be sure to leave yourself enough clearance between the tip of the bullet and the front of the magazine where the rounds will feed up 100%. Several times over the years, I have heard of hunters getting their rifle ready for a hunt. When they would go to the range to sight in, they loaded each round single shot without putting any ammo in the magazine. On getting to elk or deer camp, they find out the ammo is to long to fit in the magazine. At least they have a single shot, it could be worse. I have had hunters that their buddies loaded the ammo for them and then met them in hunting camp only to find out the ammo wouldn’t chamber from either the bullet seated to long or the case sized improperly, then they just have a club.
Four: Confirm All Cases Contain Powder
No powder in the case doesn’t seem to happen as much in rifle cartridges as in handgun cartridges. This is probably due to more handgun ammo being loaded on progressive presses and usually in larger quantities. There are probably more rifle cartridges that don’t have powder in them than you realize though. Since the pistol case is so much smaller internal capacity, when you try to fire it without powder, it usually dislodges the bullet just enough to stick in the barrel. On a rifle, you have more internal capacity and usually a better grip on the bullet, since it is smaller diameter and longer bearing surface. Like on a .223, often a case without powder won’t dislodge the bullet out of the case and just gets ejected from the rifle, thinking it was a bad primer or some little quirk.
For rifle cases loaded on a single stage press, I put them in a reloading block and always dump my powder in a certain order. Then I do a visual inspection and any case that the powder doesn’t look the same level as the rest, I pull it and the one I charged before and the one I charged after it. I inspect the one case to see if there is anything visual inside. Then I recharge all 3 cases. That way if a case had powder hang up and dump in the next case, you have corrected the problem.
On progressive presses, I try to use a powder that fills the case up to about the base of the bullet. That way you can usually see the powder as the shell rotates and if you might have dumped a partial or double charge, you will notice as you start to seat the bullet if not before. On a progressive, if I don’t load a cartridge in one smooth stroke (say a bullet tipped over sideways and I raised the ram slightly to reset it) Some presses actually back the charge back adding more powder if it has already dumped some so you have a full charge plus a partial charge. When I don’t complete the procedure with one stroke, I pull the case that just had powder dumped into it and check the powder charge or just dump the powder back into the measure and run the case through later.
L.E. Wilson Case Gage Depth Micrometer Tool Hands-On Tool Review by F-Class John
Are you looking for a better way to measure shoulder bump when sizing brass? When it comes to measuring your shoulder bump there has traditionally been just one way to do it and that’s with a set of calipers and some type of tool attached to a calipers jaw which contacts the case shoulder. While this method has worked well for decades there’s always been some inherent lack of consistency and repeatability. While a minor issue, the inability to get the exact number in completely dependent on the user’s pressure applied and the angle at which the jaws push on the brass.
Enter the L.E. Wilson Case Gage Depth Micrometer with its simple but effective use of Wilson case gauges to ensure a perfect measure of shoulder bump every time. The unit comes with the micrometer top as well as a check gauge which allows you to easily calibrate the micrometer whenever needed. On top of the micrometer unit, you’ll also need to purchase the appropriate case gauges for each of your cartridge types and then you’re ready to go. No other measuring instruments are needed (yep, no calipers are required).
Using the Wilson Depth Micrometer (perhaps a better name is Shoulder Bump Micrometer) is a straightforward process. Simply take your fired brass and insert it into the case gauge and place the micrometer top onto the primer side of the gauge. While holding the micrometer top firmly against the case gauge in one hand, slowly turn the micrometer until you feel it stop. You can back off and turn it again to verify the stop point and once you have it, look at the measurement on the micrometer. Now insert a sized piece of brass and repeat the procedure. Take note of the new number and subtract it from the fired brass number and you now have an exact amount of shoulder bump. Continue to adjust your sizing die until you have the correct amount of shoulder bump and you’re ready to size all your brass.
Watch Video to See how Shoulder-Bump Measuring Micrometer Tool Works
Guys, in this case a VIDEO is worth more than a thousand words. It may not be obvious from the photos how this system works. In fact, it is fast and easy. Drop brass into cartridge-specific case gauge, then put the Micrometer unit on top, and dial to touch. The video shows how this works.
SUMMARY — Tool is Fast, Precise, Repeatable, and Easy to Use — We Like It
The beauty of this tool is the simplicity with which it works. It uses a very accurate micrometer to simply measure how much further your brass is sitting forward inside the case gauge. After a couple uses, you’ll find that this tool is fast, accurate and incredibly repeatable. That gives you confidence that your brass is being sized properly. Ultimately, I found that using the micrometer top really became a joy as I set up a new set of dies and as I sized my brass, I could easily check the consistency as brass came off my press. If you’re looking to improve your sizing game, give the L.E. Wilson Case Gage Depth Micrometer a try. MSRP is $130.00.
.17 HMR and .22 WMR Options Enhance Ruger Precision Rimfire for Varmint Work
Many readers may not know this, but the Ruger Precision Rimfire rifle is available in two additional rimfire chamberings: .17 HMR and .22 WMR. While .22 LR ammo is considerably cheaper, .17 HMR and .22 WMR shoot flatter and deliver much more energy. This makes the Ruger rig way more suitable for varminting. In fact we think this .17 HMR transforms the Ruger Precision Rimfire into a very good “carry-around” varmint rifle. We really like the .17 HMR — it’s our favorite rimfire cartridge for small varmints out to 160 yards.
Both cartridge types, .17 HMR and .22 WMR, also offer higher velocities, less wind drift, and flatter trajectory than the .22 LR. This is a benefit when cross-training. You can shoot at more distant targets with considerably less elevation dialed in your scope. And the windage corrections will be less extreme.
Ruger says: “Faster, flatter and with high-performing bullets, .17 HMR and .22 WMR cartridges expand the capabilities of the Ruger Precision Rimfire platform. Like its .22 LR predecessor, these new magnum offerings maintain the same ergonomics, trigger and manual of arms as the larger centerfire Ruger Precision Rifle.”
Here’s an excellent video review of the .17 HMR Ruger Precision Rimfire rifle by YouTuber 22 Plinkster. The reviewer was impressed with the rifle’s accuracy with 17gr ammo.
Both Ruger Precision Rimfire rifles feature 18″ hammer-forged barrels threaded for muzzle devices, including the Ruger® Silent-SR®. The 15″ free-float handguard with Magpul M-LOK slots provides generous scope clearance and easy mounting of M-LOK-compatible rails and accessories.
Like its .22 LR version, the magnum Ruger Precision Rimfire models featured an adjustable bolt throw (that can emulate a centerfire action if desired), along with trigger that adjusts from 2.25 to 5 pounds. The .17 HMR and .22 WMR models ship with a 0 MOA Picatinny rail and one, 15-round BX-15 Magnum magazine or one, 9-round JMX-1 rotary magazine. The BX-15 Magnum is a natural pairing for the new Ruger Precision Rimfire in magnum calibers. It is also compatible with Ruger 77/17®, Ruger 77/22® and Ruger American® Rimfire rifles chambered in .17 HMR and .22 WMR.
User Review by Tommy Todd
George Gardner was kind enough to send us 50 pieces of Pre-Production Alpha 6GT brass for preliminary testing. Like the cases I formed from 6.5×47 Lapua brass, the Alpha 6GT brass will use a small rifle primer. Purchased direct from 
BRASS — The first thing you’ll find is cartridge brass choices for the 6 GT are rather limited currently. At present, the only commercial options are Hornady and 
SUMMARY — Good Cartridge with Much Potential
Barrel Velocity Variance
Oversizing cases also causes problems because the firing pin doesn’t have the length to reach the primer solid enough to ignite it 100% of the time. When you have one that is oversized, you usually have a bunch, since you usually do several cases at a time on that die setting. If the die isn’t readjusted, the problem will continue on the next batch of cases also. They will either not fire at all or you will have a lot of misfires. In a bolt action, a lot of time the extractor will hold the case against the face of the breech enough that it will fire. The case gets driven forward and the thinner part of the brass expands, holding to the chamber wall and the thicker part of the case doesn’t expand as much and stretches back to the bolt face. If it doesn’t separate that time, it will the next time. When it does separate, it leaves the front portion of the case in the chamber and pulls the case head off. Then when it tries to chamber the next round, you have a nasty jam. Quite often range brass is the culprit of this because you never know how many times it has been fired/sized and in what firearm. Back to beating it on the ground again till you figure out that you have to get the forward part of the case out.
.17 HMR and .22 WMR Options Enhance
