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March 10th, 2024

Cutaway Cartridges — Take a Peek INSIDE Loaded Ammunition

sliced cutaway ammo ammunition FOG diagram

Here’s something you don’t see every day — the inside of loaded cartridges, sliced halfway through. This lets you see how bullet core, jacket, cartridge case, powder, and primer all fit together. Give credit to the folks at FOG Ammunition for creating this interesting series of cut-through ammo images. We show four cartridges here: the .308 Winchester, 9mm Luger, 300 BLK, and .50 BMG. You’ll find two more (the .223 Remington and .45 ACP) at www.FogAmmo.com.

sliced cutaway ammo ammunition FOG diagram

This .308 Winchester model took on a different approach by only cutting the brass case and displaying the full bullet, primer and powder load. A spec amount of powder was used to create the model powder form. An estimated 10% volume was added during the forming process, along with an undetermined amount of air pockets.

sliced cutaway ammo ammunition FOG diagram

This bisection is a 9mm Luger Jacketed Hollow Point round with flake powder held together with super glue. After this self-defense round was cut by a trained professional the round was polished by hand. This might look like stick powder, but those are in fact flakes stacked up in cross-section. Designed in 1901 by Georg Luger, this popular cartridge is used by civilians, military, and law enforcement.

sliced cutaway ammo ammunition FOG diagram

For this model of the .300 AAC Blackout (aka 300 BLK), a Dremel tool was used to create a pie cut within the bullet and brass case. A measured amount of power, roughly 65% of spec charge, was placed inside the case with super glue. This cartridge was originally optimized for subsonic use with a suppressor, so the amount of powder used is small relative to the nominal case capacity. That leaves more room for the relatively large .30-caliber bullet.

sliced cutaway ammo ammunition FOG diagram

Last but definitely not least is the .50 Caliber BMG round (aka .50 Browning Machine Gun). Famed for its wartime use in the M2 Machine gun, the .50 BMG round is also used in civilian Long Range competitions. A typical .50 BMG cartridge holds over 225 grains of powder. That’s almost ten times the amount in a 5.56×45 NATO Round! To demonstrate the size of the .50 BMG, check out that .223 Rem for comparison.

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February 25th, 2024

Big Presses for Jumbo-Sized Cartridges Used in the ELR Game

Ko2m king two miles ELR .416 Barrett cheytac .50 BMG Extreme long range press

In the ELR game, particularly the King of 2 Miles (KO2M), it’s “go big or go home”. The top shooters run large-capacity cartridges that push large-caliber, ultra-high BC bullets at very high velocities. Bullets launched by cartridges such as the .416 Barrett can sustain supersonic velocities at Extreme Long Ranges — and that’s what it takes to win. The .416 Barrett can launch a 550-grain solid bullet at 3000+ FPS.

.416 Barrett cartridge ELR .50 BMG RCBS press
Photo from ELR Competitor Corbin Shell.

2018 and 2019 Kings of 2 Miles Loaded on RCBS Presses
So how do you load jumbo cartridges such as the .416 Barrett? It takes a big, heavy, super-strong reloading press. We’ve learned that two recent King of 2 Miles champions, Paul Phillips (2019) and Robert Brantley (2018) both loaded their KO2M ammo on RCBS AmmoMaster .50 BMG presses. Phillips loaded .416 Barrett ammo, while Brantley loaded a similar .416 MCS cartridge.

In 2018, Robert Brantley topped the field using his custom .416 MCS cartridge. Then in 2019, Paul Phillips won the K02M competition shooting a .416 Barrett, with Brantley a close second. Both Phillips and Brantley use the RCBS AmmoMaster .50 BMG single stage press kit and RCBS .416 Barrett dies to hand-load for extreme long-range. “My ammo has been much more consistent after switching to the RCBS press and dies,” remarked Phillips, who runs the Global Precision Group. Brantley said he uses RCBS products for most of his reloading needs — from the dies and AmmoMaster, to the ChargeMaster and Brass Boss. His custom .416 MCS loads launch a 550-grain bullet more than 3,100 fps.

Ko2m king two miles ELR .416 Barrett cheytac .50 BMG Extreme long range press

Loading with RCBS AmmoMaster .50 BMG Press
This video shows reloading with the RCBS AmmoMaster .50 BMG press. While this video shows .50 BMG cases being loaded, the principles are the same for loading the .416 Barrett cartridge or other big rounds. Big cases need big presses!

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January 11th, 2024

Lapua Will Offer 6mm GT and .300 WSM Cartridge Brass in 2024

lapua capstone brass 2024 6gt 6mmgt 6mm gt 300WSM .300 WSM 300 Winchester short magnum cartridge

Big news — Lapua will be releasing 6mm GT and .300 WSM cartridge brass in 2024! Lapua has announced the addition of two major additions to its brass lineup. In spring, Lapua will start shipping .300 Winchester Short Magnum (WSM) cartridge cases. And, in the fall of 2024, Lapua promises to offer 6mm GT brass through authorized Lapua retailers.

Lapua 6mm GT (6GT) Brass

6mm GT 6GT 6mmgt cartridge lapua brass

Lapua’s new 6mm GT brass promises to be a big hit with PRS/NRL shooters and varminters who want a bit more capacity than the 6mmBR case. The 6mm GT (aka 6GT) cartridge was conceived as a “bigger Dasher” for PRS/NRL competition. The 6mm GT’s creators wanted 6mm Dasher accuracy and moderate recoil delivered via a cartridge with a slightly longer case body for better mag-feeding, longer neck for seating flexibility, and more moderate pressures. So far the 6GT has performed very well in PRS/NRL competition. With the upcoming availability of premium Lapua-brand 6mm GT brass, we may also see a greater adoption of the 6GT in mid-range benchrest competition. We expect varminters may adopt the cartridge also, both in 6mm and necked down to .22 caliber.

lapua capstone brass 2024 6gt 6mmgt 6mm gt 300WSM .300 WSM 300 Winchester short magnum cartridge

Lapua’s Vice President of Sales & Marketing, Jarkko Aro stated, “Competitors shooting PRS, and similar long-range disciplines, have urged us to develop a 6mm GT case with unmatched quality and superior cartridge geometry to those currently offered in the marketplace. We’re confident we’ve exceeded their demands by collaborating with original cartridge developers, George Gardner and Tom Jacobs.”

6mm GT 6GT 6mmgt cartridge lapua brass

Lapua .300 Winchester Short Magnum (WSM) Brass

Available in spring of 2024, Lapua will offer a superior-quality .300 WSM case through authorized retailers. Lapua cartridge cases are known for their superb quality, consistency, and longevity. Lapua brass cases are the #1 component choice of competitive shooters in most accuracy disciplines. Lapua uses only the highest-quality materials and manufacturing processes to satisfy the demands of reloaders who seek the highest levels of precision from their .300 WSM firearm platforms.

This product release is significant news for hunters and F-Open shooters. The .300 WSM has been an effective F-Open cartridge, both in .30-caliber and necked down to 7mm. With the availability of Lapua-brand .300 WSM brass later this spring, we expect that more F-Open shooters will employ a match cartridge based on this brass.

Lapua Sales & Marketing Manager, Erkki Seikkula stated, “.300 WSM reloading enthusiasts who insist on using the best components now have Lapua cartridge cases available for their long-range target rifles and custom hunting guns. From all of us at Lapua, thank you for seeking out our components to fulfill your precision reloading needs.” Order now for delivery in spring 2024 from authorized Lapua retailers.

lapua capstone brass 2024 6gt 6mmgt 6mm gt 300WSM .300 WSM 300 Winchester short magnum cartridge

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November 12th, 2023

How to Wet-Clean Cartridge Brass with Rotary Tumblers

Frankford Arsenal Platinum Series wet liquid horizontal rotary tumbler

More and more shooters are “wet-tumbling” their brass (in liquid) with reusable polishing media, rather than using dry media in a vibratory tumbler. The “wet-cleaning” method works best with a rotary tumbler fitted with a water-tight, horizontal drum to hold your brass, cleaning solution, and stainless, pin-type media. The rotary tumbler of choice has been the Thumler’s Tumbler Model B Heavy-Duty. That is a great, sturdy machine, but now you have a more affordable option.

Frankford Arsenal offers “Platinum Series” rotary tumblers designed to clean cartridge brass with liquid and stainless media. The watertight, polymer drum rides on four rollers which rotate the drum around its horizontal axis. Two filters are provided so you can quickly separate your brass and media. A built-in timer allows you to set tumbling sessions up to three hours. There is a large, 7-liter unit and a smaller, 3.3-liter tumbler. Frankford Arsenal says the big version will clean up to 1000 cases of .223 Rem brass. That’s impressive capacity.

Rotary Tumbler Sources Online
The Frankford Arsenal Platinum Series rotary tumblers are sold by major retailers including Grafs.com, Midsouth, and MidwayUSA. Shop multiple vendors to find the best current pricing.

Amazon often has very competitive pricing on the Frankford Arsenal Tumblers, both the 7-liter unit and the smaller, 3.3-liter tumbler.

How to Wet-Clean Your Brass in a Rotary Tumbler
On our main Accurateshooter.com website, you’ll find a comprehensive review of the STM system for cleaning cartridge brass with stainless media. To clean brass with stainless media, start with five pounds of small stainless pins sold by StainlessTumblingMedia.com. Place these along with a gallon of water, a little liquid cleaner, and two pounds of cartridge brass in a rotary tumbler, and run the machine for one to four hours. After cleaning be sure to inspect all your primer holes. CLICK HERE for Brass Cleaning System Review.

Forum Member Tests STM System
Our reviewer, Forum member Jason Koplin, purchased the STM media and a new Thumler’s Tumbler. He then tested the STM cleaning procedure on his own brass, including some extremely dirty and tarnished “range pick-up” brass. Jason was thoroughly impressed with how well the STM process worked — as you can see from the “before and after” photos below. Brass which looked like it was ready for the scrap heap was restored to “like-new” appearance. The process works equally well on both rifle brass and pistol brass. Jason observed that one surprise benefit of the STM cleaning procedure is a big reduction in noise. Jason said the water-filled rotary tumbler was much quieter than his vibratory tumblers. One tip though — you should always inspect every cartridge carefully after wet-tumbling with stainless media. With large-flash-hole brass it is possible to have a pin stuck in a flash hole. This is rare, but it CAN happen.

stainless tumbling Media

stainless tumbling Media

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October 4th, 2023

Look Inside Ammo — Cutaway Cartridge Views

sliced cutaway ammo ammunition FOG diagram

Here’s something you don’t see every day — the inside of loaded cartridges, sliced halfway through. This lets you see how bullet core, jacket, cartridge case, powder, and primer all fit together. Give credit to the folks at FOG Ammunition for creating this interesting series of cut-through ammo images. We show four cartridges here: the .308 Winchester, 9mm Luger, 300 BLK, and .50 BMG. You’ll find two more (the .223 Remington and .45 ACP) at www.FogAmmo.com.

sliced cutaway ammo ammunition FOG diagram

This .308 Winchester model took on a different approach by only cutting the brass case and displaying the full bullet, primer and powder load. A spec amount of powder was used to create the model powder form. An estimated 10% volume was added during the forming process, along with an undetermined amount of air pockets.

sliced cutaway ammo ammunition FOG diagram

This bisection is a 9mm Luger Jacketed Hollow Point round with flake powder held together with super glue. After this self-defense round was cut by a trained professional the round was polished by hand. This might look like stick powder, but those are in fact flakes stacked up in cross-section. Designed in 1901 by Georg Luger, this popular cartridge is used by civilians, military, and law enforcement.

sliced cutaway ammo ammunition FOG diagram

For this model of the .300 AAC Blackout (aka 300 BLK), a Dremel tool was used to create a pie cut within the bullet and brass case. A measured amount of power, roughly 65% of spec charge, was placed inside the case with super glue. This cartridge was originally optimized for subsonic use with a suppressor, so the amount of powder used is small relative to the nominal case capacity. That leaves more room for the relatively large .30-caliber bullet.

sliced cutaway ammo ammunition FOG diagram

Last but definitely not least is the .50 Caliber BMG round (aka .50 Browning Machine Gun). Famed for its wartime use in the M2 Machine gun, the .50 BMG round is also used in civilian Long Range competitions. A typical .50 BMG cartridge holds over 225 grains of powder. That’s almost ten times the amount in a 5.56×45 NATO Round! To demonstrate the size of the .50 BMG, check out that .223 Rem for comparison.

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August 27th, 2023

Sunday GunDay: 6GT Cartridge for PRS/NRL Competition

6GT Cartridge Alpha Munitions GA Precision PRS NRL brass 6.5x47 Lapua fire-formed neck-turn project

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.

load development 6GT 6mm GT report cartridges

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 Cartridge Alpha Munitions GA Precision PRS NRL brass 6.5x47 Lapua fire-formed neck-turn project
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.

6GT Cartridge PRS NRL brass 6.5x47 Lapua 6GT 6mm Dasher cartridge fire-formed neck-turn project

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

6GT Cartridge Alpha Munitions GA Precision LabRadar PRS NRL brass 6.5x47 Lapua fire-formed neck-turn project

Alpha Munitions Pre-Production 6GT Brass
6gt brass cartridge Alpha Munitions PRS 6mm DasherGeorge 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!

6GT Cartridge 600 yard target PRS NRL brass 6.5x47 Lapua fire-formed neck-turn project

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.

6GT Cartridge 600 yard target PRS NRL brass 6.5x47 Lapua fire-formed neck-turn project

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

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-ClassBRASS — 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.

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-Class

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
mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-Class

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:

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-Class

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-ClassSUMMARY — 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:

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-Class

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.

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August 15th, 2023

Cartridge Efficiency — Factors to Consider

USAMU Handloading Guide Facebook cartridge efficiency

Efficient cartridges make excellent use of their available powder and case/bore capacity. They yield good ballistic performance with relatively little recoil and throat erosion.

USAMU Handloading Guide Facebook cartridge efficiency

Cartridge Efficiency: A Primer (pun intended!) by USAMU Staff

The U.S. Army Marksmanship Unit (USAMU) published a series of reloading articles on its Facebook Page. In this article, the USAMU discusses cartridge case efficiency and its benefits. While this is oriented primarily toward NRA High Power Rifle and Long Range (1000-yard) competition, these factors also apply to medium/big game hunters. Assuming one’s rifle and ammunition are accurate, key considerations include ballistic performance (i.e., resistance to wind effects, plus trajectory), recoil, and throat erosion/barrel life.

Efficient cartridges make excellent use of their available powder and case/bore capacity. They yield good ballistic performance with relatively little recoil and throat erosion. A classic example in the author’s experience involved a featherweight 7x57mm hunting/silhouette rifle. When loaded to modern-rifle pressures, just 43-44 grains of powder pushed a 139gr bullet at 2900 fps from its 22” barrel. Recoil in this light rifle was mild; it was very easy to shoot well, and its performance was superb.

An acquaintance chose a “do everything” 7mm Remington Magnum for use on medium game at short ranges. A larger, heavier rifle, it used ~65 grains of powder to achieve ~3200 fps with similar bullets — from its 26″ barrel. Recoil was higher, and he was sensitive to it, which hampered his shooting ability.

Similarly efficient calibers include the 6mm BR [Norma], and others. Today’s highly-efficient calibers, such as 6mm BR and a host of newer developments might use 28-30 grains of powder to launch a 105-107gr match bullet at speeds approaching the .243 Winchester. The .243 Win needs 40-45 grain charges at the same velocity.

Champion-level Long Range shooters need every ballistic edge feasible. They compete at a level where 1″ more or less drift in a wind change could make the difference between winning and losing. Shooters recognized this early on — the then-new .300 H&H Magnum quickly supplanted the .30-06 at the Wimbledon winner’s circle in the early days.

The .300 Winchester Magnum became popular, but its 190-220gr bullets had their work cut out for them once the 6.5-284 and its streamlined 140-142gr bullets arrived on the scene. The 6.5-284 gives superb accuracy and wind performance with about half the recoil of the big .30 magnums – albeit it is a known barrel-burner.

Currently, the 7mm Remington Short Action Ultra-Magnum (aka 7mm RSAUM), is giving stellar accuracy with cutting-edge, ~180 grain bullets, powder charges in the mid-50 grain range and velocities about 2800+ fps in long barrels. Beyond pure efficiency, the RSAUM’s modern, “short and fat” design helps ensure fine accuracy relative to older, longer cartridge designs of similar performance.

Recent design advances are yielding bullets with here-to-fore unheard-of ballistic efficiency; depending on the cartridge, they can make or break ones decision. Ballistic coefficients (“BC” — a numerical expression of a bullet’s ballistic efficiency) are soaring to new heights, and there are many exciting new avenues to explore.

The ideal choice [involves a] balancing act between bullet BCs, case capacity, velocity, barrel life, and recoil. But, as with new-car decisions, choosing can be half the fun!

Factors to Consider When Evaluating Cartridges
For competitive shooters… pristine accuracy and ballistic performance in the wind are critical. Flat trajectory benefits the hunter who may shoot at long, unknown distances (nowadays, range-finders help). However, this is of much less importance to competitors firing at known distances.

Recoil is an issue, particularly when one fires long strings during competition, and/or multiple strings in a day. Its effects are cumulative; cartridges with medium/heavy recoil can lead to shooter fatigue, disturbance of the shooting position and lower scores.

For hunters, who may only fire a few shots a year, recoil that does not induce flinching during sight-in, practice and hunting is a deciding factor. Depending on their game and ranges, etc., they may accept more recoil than the high-volume High Power or Long Range competitor.

Likewise, throat erosion/barrel life is important to competitive shooters, who fire thousands of rounds in practice and matches, vs. the medium/big game hunter. A cartridge that performs well ballistically with great accuracy, has long barrel life and low recoil is the competitive shooter’s ideal. For the hunter, other factors may weigh more heavily.

Cartridge Efficiency and Energy — Another Perspective
Former Lapua staffer Kevin Thomas explains that efficiency can be evaluated in terms of energy:

“Cartridge efficiency is pretty straight forward — energy in vs. energy out. Most modern single-based propellants run around 178-215 ft/lbs of energy per grain. These figures give the energy potential that you’re loading into the rifle. The resulting kinetic energy transferred to the bullet will give you the efficiency of the round. Most cases operate at around 20-25% efficiency. This is just another way to evaluate the potential of a given cartridge. There’s a big difference between this and simply looking at max velocities produced by various cartridges.”

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July 30th, 2023

Sunday GunDay: Cartridges for F-Class — Rise of the Magnums

Magnum cartridges F-Open F-Class emil kovan .300 WSM RSAUM 7mm wildcat

Cartridges for F-Class Part II — Rise of the Magnums

By Emil Kovan
Kovan Match Rifles LLC, www.matchrifles.com | READ Part I in this Series »

A few seasons back, I wrote an article on cartridge choices for F-Class shooters. CLICK HERE to READ ARTICLE. Since the first article I wrote, F-Class has continued to grow, and push the limits of precision and accuracy. While the .284 Win and its variants are still the most common F-Open cartridges, more and more top F-Open shooters are using magnum cartridge types to win competitions and set new records. In this article, I will list some of the advantages and disadvantages of the most commonly used magnums, and will cover the strengths and weaknesses of each one of them.

Performance factors we will consider for magnum F-Open cartridges include:

1. Equal or better accuracy than standard chambers
2. Better ballistic performance
3. Enhanced case life
4. Barrel life

Accuracy Potential of Magnum Cartridges for F-0pen Competition

John Meyrs has won four National Mid-Range Championships using the .300 WSM. Tim Vought used the same cartridge to win two Mid-Range Nationals and used a 7-6.5 PRC to win the long range Nationals. Standard .437″ case head (.308 Win head size) cartridges still have more Nationals wins overall, but the magnums are quickly catching up, and my prediction is that magnums will dominate soon.

The accuracy and precision potential of magnums used in F-Class (.300 WSM, 7-270 WSM, 7mm RSAUM or “7 SAUM”, 7-6.5 PRC) is better than non-magnum cartridges because their shapes are closer to the ideal “fat/short” body associated with wider nodes and extreme precision. For example a .300 WSM is proportionally much closer to the 6 PPC, 6 Dasher, and 6 BRA than is the .284 Winchester.

Magnum cartridges F-Open F-Class emil kovan .300 WSM RSAUM SAUM 7mm wildcat
Stunning F-Open rifle with SEB Mini front rest with Blake Machine accessories.

The first thing that comes to mind when magnums are discussed is power and speed. In my humble opinion most shooters are missing out on accuracy because they push their magnums right past the most stable and accurate nodes. Recently I met my good friend from the Army Marksmanship Unit, SFC Brandon Green, at a shooting competition. We discussed the latest and greatest in long-range shooting. I knew that the USAMU had switched from 6.5-284 Norma to 7mm RSAUM several years back, but didn’t know what load they are currently using. Brandon told me that the load featured Berger 180gr hybrids in Nosler cases at 2820 fps. We all know that the 7 SAUM is capable of much higher speeds, “but at around 2820 fps the load/rifle combo will hammer the X-Ring anywhere under any conditions” SFC Green said.

Magnum cartridges F-Open F-Class emil kovan .300 WSM RSAUM 7mm wildcat
F-Open rifles on the firing line at the Ben Avery Shooting Facility in Phoenix, Arizona.

Most shooters jump right into magnum territory velocities when testing, missing out on better precision at standard chamber speeds. For example, my 30 KMR can easily reach 2880 fps with 230gr Hybrids, and it actually shoots pretty good. But the same rifle at around 2770 fps will absolutely hammer the X-Ring in any condition anywhere. When it’s all said and done, F-Class is a long-range shooting competition at a known distance which requires extreme precision and accuracy. It is not a speed race.

IMPORTANT — Case-Head Dimensions Do Make a Difference
Magnum cartridges F-Open F-Class emil kovan .300 WSM RSAUM 7mm wildcat

Magnums, when shot within reasonable velocities, on average will give better case life due to the bigger case + lower pressure and “more meat” in the case-head area. For example a 7 SAUM case will outlast a .284 Win case when both are loaded to around 2900 fps.

Disadvantages of Magnum F-Open Cartridges

Perhaps the biggest disadvantage linked to magnums is recoil. Some people complain about developing the “gun shy” syndrome after shooting a magnum for a while. Muzzle blast and recoil are significantly more pronounced in magnums, but that can be easily managed with a properly-built rifle equipped with appropriate recoil mitigation hardware such as RAD and the various butt plates.

F-Open f-class recoil reduction buttpad
F-Open rifle equipped with recoil reduction buttpad system.

Barrel Life — “Barrels are Expendable Components”
It is true that certain magnums can torch a barrel in just a few hundred rounds. But the same is true when improving a 6BR to 6 Dasher for example — barrel life might be reduced significantly. More powder = more heat = diminished accuracy after a certain round count. In my experience, a F-Open magnum’s barrel life is very close to high-performance standard cartridges such as the .284 Shehane or .284 KMR. I “retire” my barrels around 1200 rounds regardless of the cartridge being a magnum or not. After that many rounds most barrels will still shoot OK but will copper up, and you will start seeing those unexplained vertical 9s. The bottom line is this, barrels are expendable components very much like brass. You can’t get the performance of .300 WSM and the barrel life of the .308 Win at the same time. If you want to race in NASCAR, fuel mileage should not be the top priority!

Top Magnum Cartridge Types Used in F-Class Open Division

.300 Winchester Short Magnum
The .300 WSM (Winchester Short Magnum) tops the popularity chart in F-Class Open division. It has been used to win numerous National championships and has set many National records. The .300 WSM’s short/fat case shape, with minimal body taper and 35-degree shoulder, contribute greatly to its outstanding performance at long range. Components are readily available as well. Best brass remains to be Norma, although ADG is just as good and some would even say better, but it is more expensive and harder to get at this time.

.300 WSM winchester short magnum  7mm .284 Win
The .300 WSM has been described as a “super-sized Dasher”.

For the .30-cal magnums, in my opinion, the best bullets by far are made by Berger. If your rifle does not shoot 215gr, 230gr hybrids, or 210gr VLDs well, you likely have a rifle problem, NOT a bullet issue. My “go to” bullet is the Berger 230gr Hybrid. The 215-grainer is a close second, followed by Berger’s accurate but ballistically inferior 210gr VLD, which I use in calm and steady conditions.

Top powders for the .300 WSM are Hodgdon H4831SC and H4350. I know there are many more powders suitable for the .300 WSM cartridge, but none I have used can match Hodgdon’s consistency when shot in different geographical locations and weather conditions.

7mm Remington Short Action Ultra Magnum
The 7mm RSAUM (aka 7 SAUM) used to be the darling of F-Open. Its case capacity and shape are about perfect for launching 180gr pills with great ballistics and precision. Its popularity faded a little, due to the lack of good brass, and the rise of the improved versions of the .284 Win which can almost match the RSAUM performance. Norma still makes 7 RSAUM brass which is pretty good but little on the soft side and hard to find. ADG is arguably producing the best RSAUM brass right now. It is very uniform, reasonably priced, and seems to hold up very well even when pushed hard. The best bullets are again made by Berger, and those are the 180gr hybrid, 184gr hybrid, and 180gr VLD. Best powders are H4831sc, H4350, and Alliant Reloder 16 and Reloder 23.

7-270 WSM, 7-300 WSM, and 7 WSM
The first two are pretty much identical, the only difference being that the 7-270 WSM is necked up .270 WSM while the 7-300 WSM is a .300 WSM necked down to 7mm. I personally prefer the first one since necking-up is easier than necking-down (with fewer doughnut issues).

The WSM case-based 7mms will give you great velocity flexibility as well as superb precision when tuned well. In the 2013 world championship in Raton NM, I was scoring for a gentleman from Canada who was shooting 7-270 WSM. The wind was blowing pretty hard that day. On one of his shots, just before he pulled the trigger the wind gusted. I remember thinking that’s going to be an 8 for sure. The target came up a line 10! I asked him after the match what he was shooting, and he replied 180s at 3100fps. Although capable of such speeds, I think that potentially better and more consistent accuracy can be achieved at much slower speeds. The best powders and bullets are again Hodgdon and Berger respectively. Best cases are made by Norma and ADG, with Winchester being a third option.

f-class magnum emil kovan wsm rsaum saum cartridge

7-6.5 PRC — Popular Wildcat
Last but not least on our chart is the 7-6.5 PRC. This particular cartridge is actually a wildcat. It is a 6.5 PRC necked up to 7mm. It is pretty much identical to the 7 RSAUM with the only differences being a shorter neck and .01″-narrower body. Currently the 7-6.5 PRC is the most requested cartridge that I offer when building new rifles. It seems to fill the gap between the .284 Win and the larger magnums very nicely. It is capable of reaching 3000fps but most shooters are getting their best results around 2920-2950 fps. The biggest advantage of this wildcat is brass. Lapua makes super high-quality, readily-available 6.5 PRC brass. Best powders are H4831sc, H4350, Reloder 16, and Vihtavuori VV 555. The best bullet in my opinion is the 180gr Berger. I am yet to hear about a better-performing bullet in this chamber.

Conclusion
Emil Kovan F-Class competition bio photoIn conclusion, magnums are not perfect but their performance advantages should be very seriously considered when building a rifle for long-range F-Class. In part three, I will list the most common wildcat magnums, and present the KMR magnums which will make you (if you haven’t already) buy a magnum action and get a magnum build for sure!

Emil Kovan
Kovan Match Rifles LLC
www.matchrifles.com

Emil Kovan Competition History:

– 2014 F-Class Open National Champion
– 2015 F-Class Open National Championship, Silver Medal
– F-Class Open National Championship Teams, 2015, 2014, 2013, Shooting Team Member
– Over 15 wins in Regional and State Championships in Palma, F-TR, F-Open
– 2013 U.S. National Team Member
– 2023 F-Open Gold Medal Team USA Member, 2023 World Championship in South Africa

Magnum cartridges F-Open F-Class emil kovan .300 WSM RSAUM 7mm wildcat

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April 23rd, 2023

Sunday GunDay: 22 Creedmoor — Versatile Varmint Cartridge

GunsAmerica Digest 22 Creedmoor

The 6.5 Creedmoor is now one of the most popular cartridges chambered in factory rifles. It found favor among hunters and PRS competitors, but then its little brother the 6mm Creedmoor became widely adopted because the 6mm version delivered less recoil, equivalent or better ballistics, and lower bullet cost.

There’s another Creedmoor cousin, the 22 Creedmoor, basically a 6mm Creedmoor necked down to .224 caliber. While this certainly can be used for PRS and tactical competition, the 22 Creedmoor seems to be ideally suited as a high velocity varmint round — something to replace the 22-250. You get 22-250 class velocities with a more modern cartridge design, and high-quality brass.

LEARN MORE about the 22 Creedmoor
There is an excellent write-up in the GunsAmerica Digest about the 22 Creedmoor cartridge. Reviewer Jeff Cramblit built a 22 Creedmoor rifle and tested it with a variety of bullet weights. He concluded it worked best as a varminter, but could also do PRS duty, provided it is loaded under the 3200 fps velocity limit common in PRS matches. CLICK HERE to read full GunsAmerica 22 Creedmoor test report.

Since there is not yet a SAAMI spec for the 22 Creedmoor, the cartridge is officially still a wildcat. However some ammo-makers have produced 22 Creedmoor loaded ammo: Copper Creek, Gunwerks, and Spark Munitions. Copper Creek has produced the most 22 Creedmoor loaded ammo varieties, with 18 different bullet options from 68 grains to 95 grains, including two lead-free bullet types. However, most everything is “out of stock” right now. Copper Creek also offers load development packs with either Peterson or Hornady brass. Here are five Cooper Creek options with Sierra and Berger bullets:

GunsAmerica Digest 22 Creedmoor

In addition, multiple companies have offered 22 Creedmoor cartridge brass: Alpha Munitions, Atlas ADG, Hornady, and Peterson Cartridge. The Peterson 22 Creedmoor brass is excellent.

Of course you can neck down high-quality Lapua 6mm Creedmoor brass. Lapua brass has outstanding consistency and durability. Choose from large primer or small primer types. Necking down is a relatively easy one-step operation with a neck-sizing or full-length sizing die. You’re just stepping down to .224 from .243 — not that big of a jump.

22 Creedmoor Brass from Peterson Cartridge
According to Derek Peterson, President of Peterson Cartridge, “We decided to build the tooling to make our .22 Creedmoor brass in response to the uptick in long-distance predator and varmint hunting. Plus the round is just straight-up fun to shoot. It is a low-recoil, flat shooting, wind-bucking round [that is] deadly accurate up to 800 yards.”

22 Creedmoor Peterson Brass

“When we designed the tooling for the .22 Creedmoor we set out to make casings with improved features”, Peterson added. “And we were successful. We increased the head hardness to tolerate higher pressures. And we increased our internal volume slightly to work better with the slow-burning powders [such as Reloder 26 or H1000].”

22 Creedmoor for Varmints — Video from the Varmint Fields of Eastern Oregon

Bullet Choices for 22 Creedmoor
If you have an appropriate twist-rate barrel, you can load the 22 Creedmoor with heavy 85-95 grain bullets. However, we think that, for varminting, the cartridge is better suited for lighter 65-80 grain bullets. This yields high velocities that provide explosive impacts on small varmints.

GunsAmerica Digest 22 Creedmoor
This GunsAmerica photo shows, L to R, 90gr Sierra MK, Hornady 88gr, 80gr, and 75gr .224 caliber bullets.

What is the Best Role for the 22 Creedmoor?
GunsAmerica tester Jeff Cramblit favors the 22 Creedmoor as a varmint round: “The performance of the 22 Creedmoor with 75-80 grain bullets makes it an outstanding varmint cartridge. I’ve seen claims of 80 grain Bergers at 3500 fps out of 26″ barrels, which would be devastating on any varmint. Loaded ammunition is available with bullets in the 70-75 range leaving 24” barrels at velocities around 3400+ fps, a bit more conservative than personal hand-loading, but still making it a very flat shooting, low recoiling round delivering impressive results.”

Jeff says the 22 Creedmoor will also work for PRS with heavier bullets: “I built the 22 CM to be a dual-purpose gun, or actually a 3-purpose gun. The first was for the coyotes and varmints previously mentioned. The second was for shooting PRS (Precision Rifle Series) style matches on occasion, and the third was for hunting deer-sized game. As with any multi-purpose tool there tends to be compromises.”

Source: The Amazing 22 Creedmoor — A Wildcat Worth a Hard Look

22 Creedmoor Cartridge Dimensions (No SAAMI Spec Yet)

22 Creedmoor Peterson Brass

More Efficient Alternatives — the 22 BR and 22 BRA

22BR 22 BR cartridge diagramIf you already have a 6mmBR rifle, and you want a higher velocity cartridge for varmint shooting, you may want to consider just necking down your brass. We’ve shot the 22 BR in the varmint fields and a steel match. This cartridge offers excellent accuracy, and is very flat shooting. We recommend getting a fairly fast-twist barrel so you can shoot the longer, high-BC bullets if you want to use your 22 BR in local matches. You’ll find that shorter 40gr to 66gr varmint bullets shoot great even in the faster-twist barrels.

22BR 22 BR boltfluter varmint rifles

For more information on the 22 BR for varminting and target shooting, with recommended loads for 40gr to 90gr bullets, read our Accurate Shooter 22 BR Cartridge Guide.

If you want more velocity than a 22 BR offers, you can have your barrel chambered for the 22 BRA (BR Ackley). With its 40-degree shoulder, the 22 BRA offers a few more grains capacity, so you can get more FPS with all classes of bullets. Fire-forming is easy — just use a normal 22 BR load with good bullets and shoot. We’ve fire-formed a 22 BRA in a varmint match and it showed excellent accuracy — there’s no need to waste bullets fire-forming. Go ahead and fire-form during a fun match.

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February 7th, 2023

The 22 BR — Versatile, Ultra-Accurate Varmint Cartridge

6mmBR 22BR 22 BR BRA varmint cartridge
6mmBR 22BR 22 BR BRA varmint cartridge

22 BR Dasher 22BRAThe 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 compare 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:

For more info on the 22 BR for varminting, read our 22BR Cartridge Guide


This article is copyright 2023 AccurateShooter.com. Any site republishing this article agrees to pay royalties and/or liquidated damages.

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January 29th, 2023

Sunday GunDay: Beyond .223 Rem — Alternative AR Cartridges

AR15 AR AR-15 cartridge alternative

Instead of using the standard .223 Remington or 5.56x45mm NATO round, you have many options for an AR-15. Dozens of cartridge variants have been tried in AR-15s. Some of the most noteworthy and popular alternative chamberings for AR-15s are:

20 Practical — This is simply the .223 Rem necked down to .204 caliber. Requires new barrel. Same bolt, same magazines. Best bang for the buck.
.224 Valkyrie — A necked-down version of the 6.8 SPC, the .224 Valkyrie was introduced by Federal a few seasons back. It has better ballistics than the .223 Remington, if used with a suitable barrel.
6mm ARC — Relatively new cartridge that works well for varminting, self-defense, tactical competitions, and deer hunting. Good selection of bullets and factory-loaded ammunition.
6.5 Grendel — Accurate and proven across the course, the 6.5 Grendel requires a new barrel, bolt, and magazines. Most use the 6.5 Grendel for competitive shooting and/or hunting.
.300 Blackout — Moderately expensive, the .300 Blackout requires a barrel change. This is used for home defense, and hunting. WARNING — with some bullets this round can be chambered in a .223 Rem barrel, with disastrous consequences.
.458 SOCOM — Pretty expensive, requires new barrel and bolt. The .458 SOCOM round is typically used for hunting though it was originally designed for Close Quarters Battle (CQB).

Of these six options, our favorite is the 20 Practical, followed by the 6mm ARC and 6.5 Grendel. The 20 Practical is a great varminting round. Check out our featured 20 Practical AR Rifle Report. This 20 Practical cartridge is highly effective on small varmints, and has shown outstanding accuracy in AR-platform rifles crafted by Robert Whitley.

20 Practical — High-Velocity, Affordable Alternative

The 20 Practical is simply a .223 Remington necked down to .204 caliber. This efficient little cartridge can launch 32-grainers at over 4200 fps, with impressive results on P-Dogs. This makes the 20 Practical a great choice for an AR-based varmint rifle.

20 Practical20 Practical Ultimate Varminter
A decade ago, as a “proof-of-concept”, 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 AR15 uppers. (The 20 Practical cartridge is simply the .223 Rem necked down to 20 caliber — you can use standard .223 brass and load with standard .223 Rem dies. Just swap in a smaller expander and use smaller neck bushings.)

6mm ARC — Popular New SAAMI Cartridge Promoted by Hornady

In June 2020, Hornady introduced the 6mm ARC, a new SAAMI cartridge optimized for AR-platform rifles*. The new 6mm ARC is basically a 6.5 Grendel necked down to 6mm, with the shoulder moved back around .030″. That pushed-back shoulder does reduce case capacity (and velocity), but we assume Hornady did that to create a shorter, proprietary chamber so people could not simply neck-down Lapua 6.5 Grendel brass, as has been done for years with Robert Whitley’s outstanding 6mm AR wildcat.

CLICK Image for official SAAMI Specifications:
6mm ARC brownells bolts cartridge loaded ammunition hornady

If you are intrigued by the 6mm ARC, you’ll find the products you need at Brownells — uppers, barrels, bolts, and magazines. Brownells also sells Hornady-made 6mm ARC factory-loaded ammo but most is out-of-stock currently. MidwayUSA currently has Hornady 108gr ELD Match 6mm ARC ammo in stock. For general information, see 6mm ARC Info Page.

What Is the 6mm ARC Cartridge?
6mm ARC brownells bolts cartridge loaded ammunition hornadyThe 6mm ARC cartridge is a modern SAAMI-spec cartridge based on the 6.5 Grendel case necked down for 6mm bullets, with the shoulder moved back 0.030. Yes it is designed to run in AR15-platform rifles. You’ll need a new barrel, bolt, and mags. If you already have an AR chambered in 6.5 Grendel, the ONLY thing you need to change is the barrel. Everything else — bolt, magazines, gas system – is compatible with 6mm ARC.

▶ Official SAAMI Cartridge (not wildcat)
▶ Fits standard AR15-platform rifles
▶ Fits Short/Mini action bolt rifles
▶ Efficient short, fat case design
▶ 30-degree case shoulder

For more INFO, see 6mm ARC Info Page.

What Do I Need To Shoot the 6mm ARC?
Faxon and Ballistic Advantage are already producing barrels, with more manufacturers sure to follow. All the other required components are already on the market for 6.5 Grendel rifles. Aero Precision already offers complete 6mm ARC uppers.

If you’re converting a standard 5.56×45 mm (.223 Rem) AR15 upper to shoot 6mm ARC, you’ll need a 6mm barrel, a Type II 6.5 Grendel bolt carrier group, and new magazines. Some folks have suggested standard AR mags will work, but trust us, you want the magazines that have been designed for 6.5 Grendel. All the hardware you need is currently available at Brownells.

6mm ARC brownells bolts cartridge loaded ammunition hornady

While 6-6.5 Grendel shooters are known to run stout pressures, the new 6mm ARC cartridge has a relatively moderate Maximum Average Pressure (MAP) rating of 52,000 psi according to the official SAAMI specifications. For a variety of reasons, is wise to keep pressures in a semi-auto rifle moderate. Don’t chase the velocities you might get in a bolt-action gun.

The 6.5 Grendel — Accurate, Plus Good for Hunters

The 6.5 Grendel round is one of the most accurate cartridges for the AR-15 platform. The 6.5 Grendel round offers a larger-diameter, .264-caliber (6.5mm) bullet running at good velocities. This provides ample energy for smaller game and deer. The 6.5 Grendel is often used for hunting deer up to 300 yards.

6.5 Grendel

History of the 6.5 Grendel Cartridge
The 6.5 Grendel originated as a 6mm PPC necked up to 6.5 mm. After Alexander Arms relinquished the “6.5 Grendel” Trademark, the 6.5 Grendel was standardized as an official SAAMI cartridge. It has become popular with target shooters and hunters alike because it is accurate, efficient, and offers modest recoil. Good for small to medium game, the 6.5 Grendel has been offered in lightweight hunting rifles, such as the Howa 1500 Mini Action.

6.5 Grendel Saami Hornady Brass

.224 Valkyrie Cartridge — Impressive with Heavy .22-Cal Bullets

224 .224 Valkyrie barrel cut-down test velocity 90gr Sierra MatchKing Fusion SP TMK

The new .224 Valkyrie was introduced in 2019 as a Hot Rod cartridge that will work in AR15s. Basically a 6.8 SPC necked down to .22 caliber, the Valkyrie has a shorter case than the .223 Remington (and 5.56×45 NATO). This allows you to load the longest, heaviest .224-caliber bullets and still feed reliably from an AR15-type magazine. Designed to rival the .22 Nosler while still running well in ARs, the .224 Valkyrie offers excellent long-range performance when loaded with modern, high-BC bullets. We expect some bolt-action PRS shooters might adopt the .224 Valkyrie. Why? Reduced recoil. With the 90gr SMK, the .224 Valkyrie offers ballistics similar to the 6.5 Creedmoor but with significantly less felt recoil. It can also be a viable alternative to a .22-250 for varminters using an AR platform.

22 valkyrie .22-250
Image from Social Regressive .224 Valkyrie Youtube Video.

Our friend Gavin Gear of UltimateReloader.com found a superbly accurate load with Berger 80.5gr bullets. Watch this video to learn more:

Sierra Bullets has published extensive load data for the .224 Valkyrie. This covers over a dozen powder types — many more than the Hodgdon database. Sierra’s .224 Valkyrie load data covers projectiles from 50 grain all the way up to 95 grains. With the 90 to 95 grain bullets, the little Valkyrie can give 6mm match cartridges a real run for their money — offering similar ballistics with less recoil. When selecting a barrel for the long .224-cal bullets, specify a fast enough twist rate: “Sierra recommends a 1:6.5″-twist barrel for the #9290 22 cal 90 gr HPBT bullet. However, for cartridges like the Valkyrie, that can push them over 2650 fps muzzle velocity, a 1:7″-twist barrel will stabilize the bullet correctly.”


CLICK HERE to DOWNLOAD Complete Sierra .224 Valkyrie LOAD DATA.

.224 Valkyrie vs. .22-250 Remington
The Social Regressive explains: “There are two key reasons why the .224 Valkyrie is unique and desirable. First, it is specifically designed to fit the limitations of the AR-15 platform. It does so even when loaded with gigantic bullets, like the 90-grain SMK that Federal announced. The .22-250 Rem is too long and too fat to work in the AR-15 platform; it needs an AR-10 bolt and magazine.”

The .224 Valkyrie has been marketed as a low-recoil round that can stay supersonic to 1300 yards and beyond (with 90gr Sierra MatchKings). Here a Sniper’s Hide duo shots an AR-platform .224 Valkyrie at distances out to 1550+ yards. To be honest, the accuracy wasn’t that impressive. However this test confirms that the .224 Valkyrie does launch the long, heavy projectiles at high enough velocities to prove superior to the standard .223 Rem. Frank Galli (aka “Lowlight”) teams up with Brian Whalen of Colorado Precision Rifle at the Blue Steel Ranch in New Mexico.

The .300 Blackout — Risky Business

The .300 Blackout appeals to folks who want a .30-caliber defense round. This can be loaded at various velocities. Loaded at subsonic speeds and shot with a suppressor, the .300 BLK offers very low sound levels. Unfortunately, that .300 Blackout cartridge can fit in a .223 Rem chamber. Shooting a .308-caliber bullet in .223 bore is a recipe for disaster.

.300 AAC Blackout 300 BLK kaboom accident blowup cartridge failure barrel .223 Rem 5.56

.300 AAC Blackout 300 BLK kaboom accident blowup cartridge failure barrel .223 Rem 5.56The .300 AAC Blackout aka “300 BLK”, is a compact 30-caliber cartridge designed to work in AR-15 rifles. It has a shorter cartridge case to accommodate the bigger 30-caliber bullet while still fitting in a standard AR-15 magazine. Unfortunately, that’s the danger. A careless shooter can toss a .300 Blackout cartridge in with .223 Rem rounds without noting. And because the case-head size is the same as the .223 Rem (5.56×45) the rifle’s bolt assembly will happily chamber and fire the .300 BLK round. Problem is, that forces a .308 diameter bullet down an undersized .223-caliber bore. Not good!

This images were provided by Tactical Rifle Shooters on Facebook. The message was clear: “Don’t try to run 300 Blackout in your .223/5.56mm. It won’t end well. The problem is identical rifles and identical magazines but different calibers.”

Image from Accurate Shooter Forum. Cutaway shows the jammed .30-Cal bullet:
.300 AAC Blackout 300 BLK kaboom accident blowup cartridge failure barrel .223 Rem 5.56

For those who MUST have a .300 Blackout, here are some things you can do:

1. Use different colored magazines for .300 Blackout vs. .223 Remington.
2. Mark .223 Rem upper handguards with the caliber in bright paint.
2. Fit all your uppers with caliber-labeled ejection port covers.
4. Mark all .300 BLK Rounds with heavy black marker.

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January 19th, 2023

Mega-Sized 14.5x114mm Round — Russia’s Colossal Cartridge

14.5x114 mm cartridge Russia South Africa
Photo courtesy Elardus de Lang, Truvelo Manufacturers Armoury, South Africa.

Believe it or not, here is a cartridge that makes a .338 Lapua Magnum look like a toy. The 14.5x114mm cartridge was designed as a MG and rifle-fired anti-materiel round. To translate from the metric system to caliber and inches, the round is a mammoth .57 caliber which measures 4.49 inches to the case mouth, and 6.13 inches overall. That jumbo-sized case holds a whopping 655 grains of powder. Commonly-loaded projectiles weigh 920-1030 grains. The 993gr armor-piercing projectile has a muzzle velocity of approximately 1006 meters per second (3300 fps) and can penetrate 30-32 millimeters of RHA steel at a range of 500 meters.

The top photo comes from Elardus De Lang, a Forum member who works at the Truvelo Manufacturers Armoury in South Africa. Elardus also provided an impressive video showing the massive 14.5x114mm being shot from prone with a Truvelo-built bolt-action rifle. Elardus tells us: “Here is a video, with a slow-motion ending, of our 14.5x114mm anti-materiel rifle being fired in our indoor testing facility. This caliber is a true beast! It propels a 993gr Armor-Piercing Incendiary bullet to 3300 fps, burning 480 grains of powder in the process. [This shows] that rifles of that power level can actually be shootable. The concussion indoors is something to experience……every shot feels like you are being punched in the face, and the heat from the muzzle flash actually hits you like a wave!”

14.5x114mm Cartridge Design and Dimensions
The 14.5×114mm has 42.53 ml (655 grains H2O) cartridge case capacity. The exterior shape of the case was designed to promote reliable case feeding and extraction in bolt action rifles and machine guns alike, under extreme conditions. Cartridges typically use lacquered steel cases, but some countries also use brass cases for the 14.5x115mm.

14.5x114 mm cartridge Russia South Africa

All dimensions are in millimeters (mm). Americans would define the shoulder angle at alpha/2, or 22.5 degrees. The common rifling twist rate for this cartridge is 455 mm (1:17.91″) with eight lands/grooves. According to official guidelines, the 14.5×114mm can handle up to 360 MPa (52,213 psi) piezo pressure.

14.5x114 mm cartridge Russia truvelo manufacturers armoury South Africa

14.5x114mm Cartridge History
The 14.5×114mm (.57 Cal) is a heavy machine gun and anti-materiel rifle cartridge used by the Soviet Union, the former Warsaw Pact, modern Russia, and other countries. It was originally developed for the PTRS and PTRD anti-tank rifles, but was later used as the basis for the KPV heavy machine gun that formed the basis of the ZPU series anti-aircraft guns that is also the main armament of the BTR series of armoured personnel carriers from the BTR-60 to the BTR-80 and for heavy anti-material sniper rifles. The cartridge was designed in 1939 and first issued in 1941.

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