FEDERAL B.O.R.LOCK Trophy Copper Muzzleloader Bullet, .50, 270 Grain - 15/boxFederal Premium has redefined modern in line performance with the Trophy Copper Muzzleloader Bullet. Its exclusive B. O. R. Lock MZ System provides outstanding accuracy in a non sabot design that's easy to load, scrubs fouling from the breech and ensures consistent bullet seating. B. O. R. Lock MZ System: Expanding polymer base cup engages rifling and seals the bore for extraordinary velocity and accuracy Non sabot design is approved for hunting in