The MK1 MOD 1-M line features 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 and lower receivers, the MK1 MOD 1-M is a no-nonsense tool for when you need a high value option that is relentless and unstoppable.Features :"16.1" 223 Wylde Barrel,Mid-Length Gas PistonPWS FSC 556 Muzzle DevicePWS Proprietary Piston Upper, T6 7075 Forged, Anodized,PWS M-Lok 15.05" Handguard,Radian Raptor Ambidextrous Charging HandlePWS MK1 MOD 1-M Multi-Caliber Lower, T6 7075 Forged, Anodized, AR-15 CompatibleMil-Spec Enhanced Trigger, PTFE Coated with 5.5 - 6.5 lbsPWS Enhanced Buffer Tube with ratchet lock castle nut and end plate set with built-in QD mount