Do primer types make a significant difference in accuracy or vertical dispersion at long range? The answer is “maybe”. Here’s one anecdotal study that tracked vertical variance among six different primer types. The tester is a good shooter with a very accurate rifle — four of the six 4-shot groups were under 2″ at 500 yards. This test doesn’t settle the question, but does suggest that it may be worth trying a few different primer types with your match ammo.
Here is a very interesting test for the 6 BRA (6mmBR Ackley) cartridge. Forum member James Phillips, a talented long-range benchrest shooter, tested SIX different primer types from three different manufacturers. To help determine vertical dispersion, James set his target out at 500 yards. He then proceeded to shoot 4-shot groups, in order, with each primer type. Velocities were recorded with a chrono. The photo above shows the results. James says: “I’ll retest the best two for accuracy and consistency with 10 shots each”. CLICK HERE for full-screen target photo.
As you can see, ALL the groups are pretty impressive. The smallest groups, 1.253″, was shot with CCI 400 primers. Next best (and very close) was CCI BR4, at 1.275″ for four shots. The “flat line” winner was the Remington 7.5, at upper left. There was almost no vertical. If you are intrigued by this interesting primer test, you can join the discussion in this Primer Test FORUM THREAD.
Primer Brand
Group Size
Velocity
Extreme Spread
Std Deviation
Remington 7.5
1.985″ 4 shot
2955 FPS
8 FPS
4.0 FPS
Federal 205M
2.200″ 4 shot
2951 FPS
11 FPS
4.8 FPS
Sellier Bellot SR
1.673″ 4 shot
2950 FPS
14 FPS
5.9 FPS
CCI 450M
2.341″ 4 shot
2947 FPS
14 FPS
6.6 FPS
CCI 400
1.253″ 4 shot
2950 FPS
3 FPS
1.3 FPS
CCI BR4
1.275″ 4 shot
2949 FPS
15 FPS
6.9 FPS
CARTRIDGE: 6mmBR Ackley, aka 6 BRA. Parent case is 6mmBR Norma. The 6 BRA is fire-formed to create a 40-degree shoulder and less body taper. Capacity is increased, but the neck is longer than a 6mm Dasher. The capacity is enough to get to the 2950+ FPS accuracy node. Some shooters say the 6 BRA is more forgiving than the 6mm Dasher. The 6 BRA is certainly easier to fire-form.
TEST REPORT — Conditions, Shooting Method, Loading Method
Tester James Phillips posted this report in ourShooters’ Forum:
Conditions: The testing was done in the morning over flags. The flags never moved or even twitched. I had as perfect conditions as I could have asked for. It was overcast so no mirage and no wind. There were no other shooters, just me.
Test Procedure: Each shot was precisely shot at my pace and centered the best possible using my Nightforce 15-55X scope. I did not use the round-robin method. Each four-shot group with the same was shot at one time. Then I moved onto the next primer. Everything felt right for each and every shot fired today. Of course I could repeat the test tomorrow and it could be exact opposite of today’s test. We can chase this forever. But [soon] I’m going to test the BR4 and 400 primer… for best accuracy and consistency for 10 shots each.
How Rounds Were Loaded: Each load was weighed to one (1) kernel of powder. So I know that’s as good as I can weigh them. Each bullet seating force was within 1# on my 21st Century hydraulic arbor press.
Previous Initial Load Testing: All groups were shot with 31.1 grains of H4895. During initial load testing I settled in on the Sellier & Bellot primer to finalize everything as it showed more promise over the CCI 450 Magnum I also tried. I was actually surprised to have seen the higher ES and SD from that primer today along with the vertical shown. [Editor: Look carefully — one shot from the CCI 450 is right in the center black diamond, stretching the vertical. By contrast the Rem 7.5 had almost no vertical.]
Velocity and NODE Considerations: I was about 5-6 FPS above what appeared to been my optimum velocity of 2943-2945 FPS, so I’ll test 5 shots of 31.0 and 5 of 31.1 and see what happens from there. I can only assume my velocities where higher due to the higher humidity and of course temps were 5 degrees warmer this morning as well. It wasn’t far off but I noticed it.
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.
1. Palmetto SA — Labor Day Sale, Deals on Optics, ARs, and More
⏺ Major savings on dozens of popular guns and products
Palmetto State Armory (PSA) is running a major Labor Day Sale with huge discounts on guns, optics, ammunition, AR components and more. We feature three of the best deals above, but there are hundreds more items on sale now.
2. KYGUNCO — CZ 600 AL Alpha Rifle, $399.99 after $100 Rebate
⏺ Price after rebate is very low for a quality hunting rifle
Here’s a great bargain on a good CZ hunting rifle. The CZ 600 Alpha rifle series is on sale now at KYGUNCO for $499.99. Plus there is a $100.00 CZ-USA rebate. This rifle is offered in five popular chamberings for the same $499.99 sale price ($399.99 after factory rebate): .223 Remington (AL1), 6.5 Creedmoor (AL2), .308 Winchester (AL2), .30-06 Springfield (AL3), and .300 Winchester Magnum (AL3).
Note: The CZ-USA website currently shows a $50 Rebate, but KYGUNCO says the rebate is $100 for purchases made in September. SEE above video.
3. EuroOptic — Vortex Optics Close-Outs, Save 40-60%
⏺ Great deals on high-quality scopes with superb warranty
Right now EuroOptic has huge discounts on Vortex optics as part of the Vortex Close-Out Sale. Save on Vortex Viper, Diamondback, Ranger, and Strike Eagle scopes. If you need an affordable scope for your fall hunt, check out the Vortex 3-9x40mm Diamondback VM-1, at just $129.99. The $150 discount represents a 54% savings off the regular price.
4. Midsouth — Large Selection of Primers IN STOCK
⏺ Huge selection of primers including popular CCI, Federal, and Remington
For the past few years, primers have been hard to find at reasonable prices. Now we are finally seeing ample inventory. Right now you can get a wide range of Rifle and Pistol Primers at Midsouth starting at $69.99/1000. In stock now are leading US-made brands CCI, Federal, Remington, and Winchester. In addition, Midsouth has large inventories of Aguila, Fiocchi, and Unis primers. We have used all these brands with success. CCI 450 primers (our #1 choice for 6BR/Dasher) are $89.99 at Midsouth.
5. RCBS Buy Green Get Green Rebates, $25 – $75
⏺ Money Back programs for all RCBS products — effectively save 16-25%
With the RCBS Buy Green Get Green promo, you get a rebate if you spend at least $100 on ANY RCBS products. There’s no restricted list of “qualifying” products. Yes this applies to reloading presses, electronic powder dispensers, ultrasonic machines, beam scales, dies — everything RCBS makes. Buy from Midsouth or other retailer. The more you spend, the more you get back — up to $75.00 total. You can submit the Rebate form by mail or you can apply online for the Rebate.
6. Powder Valley — 20% Off Winchester Hunting Ammo
⏺ Hefty 20% ammo discount right in time for hunting season
Get a 20% off rebate on Winchester hunting ammunition — Winchester Power-Point, Deer Season XP, and/or Copper Impact. This rebate comes in the form of a prepaid giftcard, with a max $50 value. Ammo must be purchased before September 30, 2023 and the Winchester Rebate Redemption Form (with receipts) must be postmarked by October 16, 2023. Buy from Powder Valley or other major vendors.
7. MidwayUSA — Walker’s Quad Connect 26 dB NRR Bluetooth Electronic Muffs, $59.99
⏺ Comfortable with excellent 26 dB NRR plus Bluetooth connectivity
These Walker Electronic Quad muffs have an exceptionally high 26dB noise reduction rating (NRR). Some other electronic muffs are rated at just 20 or 21 dB NRR, a huge difference. These are equipped with Bluetooth so you can receive calls and audio from your smartphone. These muffs boast FOUR Omni Directional Microphones, twin volume controls, adjustable frequency tuning, integrated voice mic, and really fast reaction time. If you want something thinner, the Walker’s NRR 23 Razor Slim Muffs are also on sale, for just $39.99, 33% Off.
8. MidwayUSA — Gripper Shooting Rest Bag, $29.99
⏺ Very good deal on a large, stable media-filled support bag
Here’s a versatile front rifle support bag that can be used by hunters as well as PRS/NRL competitors. Normally $42.99, this black nylon media-filled support bag is now just $29.99 at MidwayUSA. This Gripper Shooting Rest Bag has removable top straps that can hold the bag on your rifle for multi-position PRS stages. This bag works well as a front support for zeroing a hunting rifle. The bottom two legs can be manipulated to raise or lower your rifle. The Shooting Rest Bag also includes a shoulder strap.
9. Powder Valley — CCI 9mm Pistol Ammo, $12.79 for 50 Rds
⏺ Quality, USA-made brass-cased 9mm ammo at great low price
The 9mm Luger (9x19mm) is the most popular cartridge for CCW, gun games, and handgun training. Right now you can get excellent CCI Blazer 9mm FMJ ammo for just $12.79/box at Powder Valley. Chose either 115 grain or 124 grsom FMJ for the same $12.79 price for a 50-rd box. We have used this brass-cased ammo in SIGs, HKs, and Glocks and it proved 100% reliable with good accuracy.
10. Amazon — XAegis Tactical Eyewear, $18.99
⏺ Under $20 for versatile, multi-lens Eye Protection
All shooters need quality eye protection when operating firearms. XAegis Tactical Eyewear is a versatile and affordable option. These ANSI Z87+ rated shooting glasses come with three different interchangeable lenses (Clear, Yellow, Gray). You also get a transport case, lanyard, and cleaning cloth. Choose from three frame colors, each for $18.99: Black, Khaki, or Green. For under $20 these are hard to beat. It’s nice to have the color lens options for different weather conditions, and indoors/outdoors.
Here’s an inexpensive product that can make your case prep and loading tasks easier. We use and recommend the cleverly-designed Lyman Bleacher Blocks. These multi-level (stepped) cartridge holders save space on your bench AND make it easier to select a particular case/cartridge from a full block. Each row is a different height for convenience. With Bleacher Blocks it’s also easier to check for powder levels, or place bullets before the seating process.
Lyman’s Bleacher Block cartridge holders have many advantages over conventional, single-level blocks. Use the different levels for sorting brass. Or, migrate the brass from top to bottom as you proceed through case prep stages. If you are assembling loads with different bullets for load testing, you could arrange the loaded rounds on different levels for easy recognition. For example put V-Max loaded rounds on the top tier, and Berger Hybrid loaded rounds on the bottom tier. Or, if you are experimenting with neck tension, you can use different rows for cases processed with different bushings.
Made of durable orange polymer, Lyman Bleacher Blocks are now molded in five sizes — small pistol, large pistol, and three rifle sizes. The smallest rifle block (with 0.388″-diam holes) fits .223 Rem-size case heads. The middle size rifle block (with 0.485″-diam holes) fits .308 Win-size case heads. That works for 6mmBR/Dasher sized cases perfectly. The biggest rifle Bleacher Block has 0.565″-diameter recesses for magnum-size cases. All cartridge block sizes hold fifty (50) rounds. Purchase these for just $6.29 per block at Midsouth or get them for $7.99 per block at Brownells.
Here’s what Lyman says about its innovative cartridge block design: “Our [stepped] loading blocks allow for easier handling of cases in and out of the loading block. Our stepped design allows you to easily grip a single case without jamming your fingers down into a group of cases like in traditional loading blocks, and allows for a smaller ‘footprint’ on your bench.”
Lyman Bleacher Blocks are among the Reloading Tools reviewed in this helpful video:
Many online vendors are running sales this Labor Day Holiday weekend. You’ll find scores of products marked way down, plus discount codes that can save you 20% or more on your purchases. Many sales run through the end-of-day on Monday, September 4th, while other Labor Day sales extend further. Be sure to check the sale schedules.
Here are links to seven notable Labor Day sales. With these Labor Day promotions you can save 10-40% on some items. In addition, some of the vendors are offering FREE Shipping and/or FREE Hazmat (for primers and powder shipping) with a minimum purchase.
Precision Reloading — 10% Off Sitewide with $99 Minimum Order
Right now at Precision Reloading, if you spend at least $99.00, you can get 10% Off on nearly everything on the site now through September 4 at 11:59 pm. Save 10% this Labor Day weekend on orders over $99 with Coupon Code 9123 at checkout.
Brownells — 410+ Sale Products Plus 10% Off with Code LD10
Brownells is running a big Labor Day promotion. Go to the Labor Day Sale Page to find over 410 products discounted up to 40%. Featured items include Federal Gold Medal Ammo, Winchester Rimfire Ammo, Reloading Powders, Hornady Presses, Lee Reloading tools, AR components, and optics. In addition, with special Code LD10, you save an extra 10% on products featured in the 2023 Brownells Labor Day Sale.
Primary Arms — Labor Day Sale
There are some amazing deals this Labor Day Weekend at Primary Arms. All in-stock gun cases are on sale. Bipods from Harris, Magpul, and Atlas are on sale. A large selection of optics are deeply discounted with big savings on Trijicon and Holosun Red Dot sights. And rifle components are discounted — for example you can get a Precision Arms mid-length AR-15 barrel for just $59.99.
Midsouth — Free Shipping or HazMat with $99+ Orders
Celebrate Labor Day with Free Shipping Or Hazmat on Midsouth orders over $99.00. For an Order to Qualify for FREE Shipping (LDFS23) the order must Include $99 of In Stock items Up to 49 lbs. If order weight exceeds 50 lbs, a shipping charge will be assessed for the overage. For an order to qualify for FREE Hazmat (LDHM23) the order must include $99 of In-Stock Hazmat items. This promotion is for Retail Customers only. No backorders. Lower 48 States only. Offers cannot be combined. Offer ends 9/4 at 11:59 pm CST.
L.E. Wilson — 10% Off Sitewide (Except Presses)
L.E. Wilson currently offers 10% OFF all online orders. Take advantage of these special Labor Days Weekend savings on outstanding Wilson tools and dies. NOTE: The 10% Off discounted prices are already reflected in the Wilson online shopping cart total. The 10% discount does NOT include reloading presses.
Mesa Tactical — 10% Off Sitewide
Starting Friday, September 1st through Monday, September 4th use coupon code LABOR10 to receive 10% OFF sitewide at Mesa Tactical. Popular products include rifle stocks, adjustable fore-ends, and shotshell carriers. You also get a free Mesa Tactical Operator’s Cap with orders over $150.00.
SilencerCo — Up to 30% Off
SilencerCo is running a major Labor Day Sale now through September 4, at 11:59 PM MDT. You can save 25% off sitewide and 30% off product bundles. SilencerCo states: “There’s never been a better time to start working down that laundry list of suppressor accessories.”
Lapua has hired skilled competitive shooter Ryan Sponauer as the new Rimfire Performance Center Manager for the sophisticated Lapua rimfire ammunition test center in Mesa, Arizona. At that center, rimfire rifle owners can test lots of Lapua rimfire ammo in their own rifles. In the Mesa, Arizona facility as well as other Lapua Rimfire Performance Centers, visitors can test lots of ammunition at both 50 and 100 meters simultaneously to determine which lots shoot best in their guns.
Sponauer brings a long and accomplished competitive shooting background to Mesa’s Lapua Rimfire Performance center. He started with three-position and prone at the age of 14 at The Blue Trail range in Wallingford, CT, where he won numerous state and regional matches. Sponauer, who graduated from the University of North Georgia, shot for their NCAA 3-P and Air Rifle teams, served as multi-year team captain, and managed lot testing ammunition for the team. Sponauer and his team went on to win the 2021 Southern Conference Championship.
Sponauer commented: “I am very excited to give back to the shooting community with this position because the sport has given me so much. The lot testing we offer gives any shooter a significant competitive edge allowing them to compete to their maximum potential.”
Patterned after the world-renowned Lapua Test Center in Germany, both the Marengo, Ohio, and Mesa, Arizona Lapua Rimfire Performance Centers allow shooters to test multiple lots of ammunition under tightly-controlled conditions. Each of the Lapua Rimfire Performance Centers offer the ability to test ammunition at both 50 and 100 meters, simultaneously. By comparing the results of various ammunition lots at both distances, the best performing lots can offer a competitive advantage. To learn more about the Lapua Rimfire Performance Centers or to schedule an appointment, visit Rimfiretest.com.
About Lapua
For 100 years, Lapua has been producing the highest quality small caliber cartridges and components for civilian and professional use. Lapua is a part of the Capstone Precision Group, exclusive U.S. distributor for Berger, Lapua, Vihtavuori and SK-Rimfire products. For more information, visit Lapua.com
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.
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
