Federal Premium’s® .50-cal. 350-gr. Lead Muzzleloader Bullets with the exclusive B.O.R. Lock MZ™ System provide outstanding accuracy in an easy-to-load sabot-free design. Ignition pushes a permanently attached polymer cup onto raised bands along the bullet shank, expanding its diameter and engaging the rifling to seal the bore, optimizing both velocity and accuracy. At the rear of the B.O.R. Lock MZ cup is a hard, fiber-reinforced polymer ring that scours fouling from the breech as the bullet is pushed into place. This decreases the need to clean between shots and makes it easy to seat the bullet at the same depth for every shot. With no bulky sabot, required loading force averages about half of most sabot bullets. Features a polymer tip with a deep, hollow cavity and skiving that delivers consistent, devastating expansion. Per 15.