Luth-AR Commerical Scallop Carbine Buffer Tube AR-10/ AR-15 5.56x45mm Nato/ 7.62x51mm Nato 7.25in Length 6 Positions 6061-T6 Aluminum Anodized Black. This Carbine Buffer Tube works with their MBA-3 MBA-4 and MBA-5. Specifications for Luth-AR...