Abstract: A cylindrical plug that is configured to be removably inserted into the breech of a breech-loading firearm, converts the firearm to one of a muzzle-loading type. The plug is provided with a primer-receiving chamber at one end, a powder charge chamber at the other end, and a passage that establishes communication between the two chambers. The primer-receiving chamber is adapted to receive a percussion-type primer, detonation of which generates ignition products which are communicated via the flash to a main powder charge situated in the charger chamber of the plug to cause combustion of said charge and propel a projectile or projectiles from the firearm. Alternatively, the plug is structured so that it can function as a reusable casing for holding a powder charge and a projectile or projectiles to function, for example, as a shotgun shell.

Abstract: A conversion plug that is configured to be removably inserted into the breech of a breech-loading firearm, converting the firearm to one of a muzzle-loading type. The plug is provided with a primer-receiving chamber at one end and a series of passages that communicate the chamber to a region proximate the other end. The primer-receiving chamber is adapted to receive a percussion-type primer, detonation of which generates ignition products which are communicated via the series of passages to a main powder charge situated at the interior end of the plug to cause combustion of said charge and propel a projectile from the firearm.