Muzzleloader systems include a pre-packaged propellant charge with a primer receptacle for providing efficient loading and unloading of the muzzleloader. The muzzleloader accepts in the breech end a propellant containment vessel that abuts against a constriction portion with a reduced diameter portion. The propellant containment vessel having an end portion with a tapered surface that conforms to the constriction portion surface. A projectile is inserted in the muzzle end of the muzzleloader and seats against the constriction portion.