Although already available to the public by a number of major manufacturers, it’s exciting to see the 338 ARC, 25 Creedmoor, and 7mm Backcountry have been accepted by the Sporting Arms & Ammunition Manufacturers’ Institute (SAAMI) and given official specs.
If you’re unfamiliar, the SAAMI is a non-government governing body that provides standardization for cartridges in the United States. This includes manufacturing tolerances for chambers and cartridges, maximum safe pressures, and expected baseline performance. This not only helps manufacturers produce these cartridges on a large scale but also makes it so that 9mm Luger (or any approved cartridge) from one brand fits and functions in another brand.
Cartridges outside of SAAMI’s approval are often called “wildcat” cartridges since they are not standardized.
338 ADVANCED RIFLE CARTRIDGE – HORNADY
Blurring the line between the performance of 300 Blackout and 8.6 Blackout, 338 ARC is a small-AR frame cartridge mostly focused on subsonic performance with ~300-grain bullets. Built to be easier to suppress with fewer gas issues in an AR than 300 BLK, the 338 ARC offers some solid performance upgrades over 300 BLK.
Using the much larger bullets 338 ARC, on paper, should deliver more energy to the target than what 300 BLK can offer and should perform on par with 8.6 Blackout while subsonic.
For supersonic, 338 ARC uses ~175-grain bullets at ~52,000 PSI chamber pressure.
7MM BACKCOUNTRY – FEDERAL
Built with a new steel alloy exclusive to Federal the 7mm Backcountry is basically a civilian-focused version of SIG Sauer’s .277 FURY that has been adopted for the Army’s XM7 program. Boasting an incredible 80,000 PSI chamber pressure, 7mm Backcountry claims to send a 170-grain bullet at a screaming 3,000 FPS with only a 20” barrel.
This acceptance by SAAMI comes with a warning for manufacturers:
“WARNING: Maximum Average Pressure levels greater than 65,000 psi may present increased risk of unsafe cartridge case or firearm rupture and thus require cartridge case and/or firearm designs that depart from traditional practices (materials, construction, and other design criteria).”
Due to Federal’s special alloy being proprietary, it’s unclear when or if we’ll see more ammo being offered by other brands for the 7mm BC.
25 CREEDMOOR – HORNADY
Arguably the best of the Creedmoor family, 25 Creedmoor’s life story starts about 100 years ago with the Savage .250-3000 (a cartridge you’ve probably never heard of). A long time later, Hornady is reviving the .257 caliber idea after copying a good amount of homework done by wildcatter’s like Black Jack bullets.
Shooting 130ish-grain bullets with 62,000 PSI chamber pressure produces muzzle velocities of around 2,800 FPS. This offers less recoil than 6.5 Creedmoor, higher BC bullets than 6mm Creedmoor, and better barrel life than either of them.
This little-known caliber is actually seeing a lot of support from major brands. Brass is available from Peterson and Alpha Munitions. Berger, Hornady, and Barns offer bullets in .257 caliber that are extremely well-made and optimized for long range shooting.
And all of this was before SAAMI acceptance. We’re excited to see what happens next for 25 Creedmoor!
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