Shop › ROSCO BL BBL 16" 300BLK HB 1/8 ROSCO BL BBL 16" 300BLK HB 1/8 $178.20 Rosco Manufacturing Bloodline Heavy Barrel, 300BLK, 16", Black Nitride Finish, 1:7 Twist, 5/8x24, 4150 CMV BL-16-HB-300BLK-8-P Add To Cart Added! Rosco Manufacturing Bloodline Heavy Barrel, 300BLK, 16", Black Nitride Finish, 1:7 Twist, 5/8x24, 4150 CMV BL-16-HB-300BLK-8-P