A Wildcat Cartride I like: .30 ARX

Nathan S
by Nathan S

Now here is a wildcat that I can get behind. The .30 ARX is an immediately semi-auto AR-15 compatible cartridge. It’s nothing special from a manufacturing standpoint; as the cartridge creator claims, the .30 ARX is simply a necked-up 6.5 Grendel to accept common .30 caliber bullets.

But, by changing the case from a .223 base to a 6.5 Grendel base, the user immediately gains 14 grains of case capacity (no bullet loaded) over the 300 BLK. This gives shooters using the right powders the ability to get to nearly 30-30 load performance while still being able to use the relatively common 6.5 Grendel bolts.

Personally, I like this over the 300 BLK, simply from a mechanical design standpoint. While there is the issue of less common components, the higher-taper cartridge will make feeding and extraction more reliable. Plus, it solves what I consider one of the detriments of 300 BLK, its lower supersonic velocity (again, relatively speaking).

The .30 ARX is still a wildcat loading, but tools are available for the reloader to easily manufacture this round at home. Those interested in the cartridge can see more details, purchase dies and other components, and check load data at AR-X Enterprises.

Nathan S
Nathan S

One of TFB's resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR's, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.The above post is my opinion and does not reflect the views of any company or organization.

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  • OldOldLawyer OldOldLawyer on Aug 08, 2015

    Not sure why this is an article...it does not even give one velocity comparision with the 300 blackout....those of us who jumped on the 300 aac bandwagon early did so because of the subsonic capability....shooting hogs, or deer, or coyotes at 100-150 yards with 200-220 grain slugs with little noise is no small feat......deer, coyotes, etc dont know where the sound comes from..hogs will often just stand and look around as their mates fall over....in those roles, there is zero reason for more case capacity to push a big bullet slowly......and you can play sniper without hearing protection....I love wildcats, but if the new round does not give say 15% more velocity then what is the use....and why not at least once velocity comparision?

    • Ostiariusalpha Ostiariusalpha on Aug 08, 2015

      @OldOldLawyer The truth is .300 Blackout starts to lose velocity with bullets over 220gr, and you basically want to keep your muzzle velocity as near beneath transonic as possible. Otherwise, your wasting the potential inertia of the heavier bullets. If you're fine with 220gr subsonic loads, .300 BO is going to fit your needs more than adequately. As for the velocity difference between this wildcat and the puny Blackout case, exact numbers comparing weight-for-weight would sure be nice, but simple logic says that a +50% jump in case capacity will substantially increase any projectile speed.

  • Jon Pitchford Jon Pitchford on Aug 08, 2015

    Or, you could just build a 7.62x39 upper and save a lot of money on ammo.