I may be the last person to have heard, but CMMG is making AR-style rifles chambered for the .300 BLK cartridge. Â (As it turns out, I was not. Â I got an e-mail from a guy who had been stranded in the arctic for the past six months who had not heard about these rifles either.)
Essentially, there are four variants of the M300 Blackout rifle. Â All four of the carbines have 16″ barrels with 1:8 twistÂ and a six position M-4 style buttstock. Â Two of the models have a flat top receiver, no sights and a mid-length quad-rail.
The other two CMMG M300 versions have the flat top receiver, A2 front sight, Magpul rear BUIS and the standard carbine length handguard (no rails).