Piston driven with an adjustable 2-position gas block for suppressed and unsuppressed shooting. It also had a bit shorter hand guard to allow for the bayonet lug on the bottom of the gas block. 14.7“ barrel. SUREFIRE WARCOMP flash hider (pin & welded) I might have shot it once but not sure. Sits in safe. No trades. $1,775.00 O.B.O
