The MOD1 MK109 Primary Weapons upper in caliber 300 Blackout features MLOK handguard, Triad compensator, 41V50 FNC LIFE HD barrel, PWS long-stroke piston system, FNC LIFE HD bolt carrier & Radian Raptor LT charging handle.
PWS advises the use of supersonic 110 to 130 grain ammo on this platform. Running ammunition heavier than 130 grain can adversely affect cycling unless a suppressor is utilized.