The 6.8x43 mm SPC cartridge was designed to deliver improved terminal performance out of the AR-15/M16 platform, literally doubling the bullet weight over the conventional 5.56x45 mm, while still being able to use the same lower receiver. Change out the upper and the magazine, and you have a much harder-hitting platform without a substantial weight penalty.
But the guys at LWRC, including Senior Design Engineer Jason Miller, were not happy with magazine reliability using existing AR magazines with a just new follower. The magazine is the heart of any firearm; if your magazine is not 100 percent reliable, your entire platform suffers.
So LWRC went to Magpul and asked for a larger magazine designed specifically for the 6.8x43 mm SPC, and it ended up slightly larger than a standard AR magazine. That required a new lower receiver to accommodate it. Thus, the SIX8 family from LWRC that includes the Special Purpose Rifle (SPR), the A2, the A5, the Ultra-Compact Individual Weapon (UCIW) and the SIX8-Pistol, which are all built on LWRCI’s proprietary short-stroke, gas-piston system. The guns are made in semi-automatic, selective-fire and are offered as short-barreled rifles as well.
I had the opportunity to shoot the 16”-barreled SIX8-SPR on a recent field trip to Cambridge, Md., where I made steel plates ring with almost monotonous regularity, I also interviewed Miller about the changes they had to make to the gun and magazine. You can see the video above or directly on our YouTube channel.