A conversion kit for a projectile launching device having an outer configuration, the projectile launching device having a barrel, the projectile launching device having a projectile receiver that is connected to the barrel and that is capable of being connected to a projectile hopper, the conversion kit comprising: at least one shell (31A, 31B) which is capable of being secured on a projectile launching device; each shell (31A, 31B) further comprising an inner surface, and at least one first mating surface on the inner surface; each mating surface being capable of being held in tension against a corresponding second mating surface on an outer surface of the projectile launching device to increase stability of the at least one shell (31A, 31B) when mounted on the projectile launching device; the at least one shell (31A, 31B) being configured and arranged to define a pass-through aperture to permit the projectile receiver of the projectile launching device to extend outwardly beyond the at least one shell (31A, 31B) while the at least one shell (31A, 31B) is mounted on the projectile launching device, an entry port of the projectile receiver being outside the at least one shell (31A, 31B) to enable engagement with a projectile hopper for the supply of projectiles to the projectile launching device while the at least one shell (31A, 31B) is mounted on the projectile launching device; whereby the at least one shell (31A, 31B) changes the outer configuration of a projectile launching device onto which it is secured; whereby the operation of the at least one shell (31A, 31B) is configured so that it does not affect the operation of the projectile launching device; wherein the at least one shell (31A, 31B) is configured so that it does not interfere with the barrel of the projectile launching device while the at least one shell (31A, 31B) enshrouds the projectile launching device such that the barrel is removable from the projectile launching device without removing the at least one shell (31A, 31B) from the projectile launching device. at least one shell (31A, 31B) which is capable of being secured on a projectile launching device; each shell (31A, 31B) further comprising an inner surface, and at least one first mating surface on the inner surface; each mating surface being capable of being held in tension against a corresponding second mating surface on an outer surface of the projectile launching device to increase stability of the at least one shell (31A, 31B) when mounted on the projectile launching device; the at least one shell (31A, 31B) being configured and arranged to define a pass-through aperture to permit the projectile receiver of the projectile launching device to extend outwardly beyond the at least one shell (31A, 31B) while the at least one shell (31A, 31B) is mounted on the projectile launching device, an entry port of the projectile receiver being outside the at least one shell (31A, 31B) to enable engagement with a projectile hopper for the supply of projectiles to the projectile launching device while the at least one shell (31A, 31B) is mounted on the projectile launching device; whereby the at least one shell (31A, 31B) changes the outer configuration of a projectile launching device onto which it is secured; whereby the operation of the at least one shell (31A, 31B) is configured so that it does not affect the operation of the projectile launching device; wherein the at least one shell (31A, 31B) is configured so that it does not interfere with the barrel of the projectile launching device while the at least one shell (31A, 31B) enshrouds the projectile launching device such that the barrel is removable from the projectile launching device without removing the at least one shell (31A, 31B) from the projectile launching device.