Patent ID: 8096075

Claim:
A breech plug for use in a muzzleloading firearm having a barrel with a muzzle end and a longitudinal bore extending rearward from the muzzle end to a rear barrel portion with a breech plug chamber having an initial portion having a tapered section, the rear barrel portion defining an aft facing surface, the breech plug comprising: a cylindrical body having an external threading and defining a bore and a longitudinal axis therethrough; a substantially circular flange being located rearward from the external threading and having an outer diameter being substantially larger than both the major diameter of the external threading and an inner diameter of the aft facing surface; and a cup element extending forward from the cylindrical body, the cup element having a base and a cylindrical side wall, the base being spaced longitudinally rearward from a forward end of the cylindrical side wall and forward of the external threading, the forward end of the cylindrical side wall being located at a distance from the substantially circular flange to allow the cylindrical side wall to act against the tapered section of the barrel to deform in a radial direction forward of the base when the substantially circular flange is positioned adjacent to the aft facing surface of the barrel.