Muzzleloader systems

A muzzleloader firing system comprising:

• a muzzleloader having a barrel with a breech chamber, a constriction portion and a projectile bore portion, the constriction portion having a surface facing a breech end and a surface facing a muzzle end, wherein the diameter of the bore of the projectile bore portion is greater than a minimal diameter of the constriction portion
• a hermetically sealed propellant cartridge, the cartridge having a head connecting to a cup portion with a cylindrical wall and an end portion, the end portion having a tapering portion, the cylindrical wall portion, and the end portion unitary with each other and defining a closed forward end, the head having a recess for a primer, the head and cup portion defining a cavity with propellant sealed therein, and
• a projectile for insertion in the muzzle end, wherein the projectile comprises a bullet system, comprising a bullet body and a polymer cup, the bullet body having a forward tapered end and a rearward tail portion, the tail portion having a tapered region with a radius of the tail portion increasing in the forward direction, the polymer cup with a closed rearward end, the polymer cup axially movable on the exterior of the bullet body, the bullet system having a first axial elongated state wherein the cup is positioned rearwardly on the bullet body with a corresponding initial radius that facilitates the loading of the bullet down the barrel, and a second axial shortened state wherein the cup is positioned forwardly compared to the first axially elongated state, the second axial shortened state with a corresponding radially expanded portion of the polymer cup that is greater than the initial radius and provides a sealing of the bullet system with a barrel during firing, the corresponding radially expanded portion of the polymer cup effected by way of the polymer cup engaging a camming surface on the bullet body when the bullet transitions from the first axially elongated state to the second axially shortened state, the expanded portion having a maximum diameter that is rearward of a the forwardmost edge of the polymer cup.