Cartridge for muzzle loading firearms

A cartridge for a muzzle loading firearm, the cartridge comprising:

• a cylindrical sleeve portion formed from a non-combustible material that defines an interior passage, the sleeve portion comprising a forward end relative to a firing direction comprising a tapered portion that defines an aperture with a cross-sectional area that is less than a cross-sectional area of the interior passage, and a rearward end portion that is arranged adjacent to an opposite end of the cylindrical sleeve portion and is separated from the forward end by the interior passage, wherein the sleeve portion is devoid of a retention feature that cooperates with a portion of the muzzle loading firearm that interferes with expulsion of the sleeve portion through a muzzle of the muzzle loading firearm so the sleeve portion is expelled from the muzzle in response to a discharge of the cartridge;
• a propellant charge disposed within the interior passage;
• a membrane provided to the rearward end portion to be positioned adjacent to a closed rear of a barrel and substantially enclose the propellant charge disposed within the interior passage;
• an end cap comprising a peripheral wall that defines a recess into which the tapered portion extends with the end cap installed over the tapered portion, wherein the end cap comprises a first fastener portion;
• and
• a bullet comprising a second fastener portion that is compatible with the first fastener portion of the end cap, the second fastener portion being disposed adjacent to a rearward end of the bullet to establish a friction fit between the bullet and the end cap that maintains a position of the bullet on the cartridge to be loaded into the muzzle loading firearm.