Ar-15 Mk1 Mod 1-M Upper Receiver Assembly 300 Blackout M-Lok - Mk109 Mod 1-M 300blk Upper Receiver W/9.75'''' Bbl

PRIMARY WEAPONS AR-15 MK1 MOD 1-M UPPER RECEIVER ASSEMBLY 300 BLACKOUT M-LOK The Primary Weapons Systems MK1 MOD 1-M line of upper receivers feature the PWS long stroke piston system. Internally, this line offers the tried and true system that PWS owners have grown to know and love. Featuring a free-float MLOK handguard, forward assist controls, and a more true to mil-spec design, the MK1 MOD 1-M line is a go-to for not only civilians, but also Law Enforcement. With the fully forged upper, the