The Firearm Blog

SayUncle reported that Bison Armory are selling new 6.8 SPC AR-15 upper recievers. From BisonArmory.com:

We just got our 18″ and 20″ 6.8 SPC barrels today! I’ve put together the first upper for testing. It’s a 20″ with unthreaded muzzle. Pictured below is the upper with a Young Mfg. Match bolt carrier, YHM lightweight four-rail rifle length hand guard, and YHM A3 flat top upper receiver. The upper also features an intermediate-length gas system, YHM low profile gas block, and YHM forearm end cap.

These photos of the uppers were posted on 68forums.com:

The first upper is the most basic, 20″ with threaded muzzle, Phantom .308 FH, Bushnell 3-15×50 scope and rifle length gas system. The second one is the 20″ unthreaded with intermediate-length gas system.

The first upper in this photo is an 18″ with a Saylors Machine Phoenix FH and mid length gas system. The bottom one is an 18″ with a TNW gas piston system and DPMS Levang linear compensator. I’m really looking forward to trying out the GP system.

The 6.8×45mm is an alternative to the 6.8 SPC cartridge that has been getting a lot of attentio. Developed by Larry Kramer of Kramer Defense (They have no website that I could find). The parent cartridge is the .223 Remington / 5.56mm NATO.

Its advantage over the 6.8 SPC is that a standard AR15 bolt face and magazine can be used, and that the case can be formed from .223 brass instead of the obscure .30 Remington.

5.56mm vs. 6.8×45mm.
Photo from Defense Review.

The 6.8 SPC can send a 115 gr bullet at 2625 ft/s while the 6.8×45mm Kramer can push the bullet to 2500 ft/s. Kramer claims that once the round is refined it will be able to achieve 2600 ft/s from a 16″ barrel.

A lot of development has gone into the SPC by Special Forces members and Remington. I think it is likely that they would have tried the .223 case as it would be a logical choice for the next AR/M16 cartridge. I know very little about wildcats and cartridge development but I would guess there was a good reason they went with the .30 Rem as a parent instead of the .223 Rem.

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