The Dead Foot Arms AR9 uppers—AR9-SD and AR-MP9—are assembled as complete, direct-blowback upper receivers chambered in 9mm. The non-reciprocating, forward-charging receivers will attach to most AR9 and AR-15 lower receivers. The included full-auto-compatible 9mm bolt carrier group will work with Glock, Colt, Endo and MP5 magazines. These uppers also come with MP5 blade-style front sights and a rear sight drum. Handguard options include an MP5 SD-style aluminum unit with three M-LOK slots and an MP5 wide-style polymer forearm. Uppers available in 8- or 16-inch configurations.