Sons of Liberty Gun Works 13.9 in Patrol SL Upper Receiver Group w/NOX mount FSB 5.56mm Black PATROLSLUPPER-13.9-556. These feature 1:7 twist 4150CMV Nitride finished barrels with true 5.56mm NATO chambers taper pinned F-marked front sight bases...
Sons of Liberty Gun Works 13.9 in Patrol SL Upper Receiver Group w/NOX mount FSB 5.56mm Black PATROLSLUPPER-13.9-556. These feature 1:7 twist 4150CMV Nitride finished barrels with true 5.56mm NATO chambers taper pinned F-marked front sight bases...