GC_UPC Bushmaster 0040004BLK M4 Patrolman's Upper 5.56x45mm NATO 16" Black Nitride Barrel, 7075-T6 Aluminum Black Receiver, M4 Handguard for AR-Platform $591.20 0040004BLK show more like this 8.95 Beebe Family Arms & Munitions GC_UPC Bushmaster 0040004BLK M4 Patrolman's Upper 5.56x45mm NATO 16" Black Nitride Barrel 7075-T6 Aluminum Black Receiver M4 Handguard for AR-Platform $591.20 0040004BLK show more like this $10.95 flat rate GunStuff TV GC_UPC Bushmaster 0040004Blk M4 Patrolman's Upper 5.56X45mm Nato 16" Black Nitride Barrel, 7075-T6 Aluminum Black Receiver, M4 Handguard For Ar-Platform 91822 $602.80 91822 show more like this Firearms $18.45, Free over $500 Shooting Surplus GC_UPC M4 Patrolman's 0040004BLK $634.86 0040004BLK show more like this 9.99-29.99 Per Item Gunprime GC_UPC BUSHMASTER M4 PATROLMAN UPPER RECEIVER $640.99 - show more like this 7.99 Guns.com