This box of .22 Rimfire, according to author George Kass, was the only example he did not have in his voluminous collection. It is so rare that nobody knows who the maker was. American cartridge manufacturer Union Metallic Cartridge Company most likely introduced the 22 Long Rifle cartridge as early as 1884. The round owes its origin to the 22 BB Cap of 1845 and the 22 Short of 1857. It combined the case of the 22 Long of 1871 with a 45-grain (2.9 g) bullet, giving it a longer overall length, a higher muzzle velocity and superior performance as a hunting and target round, rendering the 22 Extra Long cartridges obsolete. The 22 LR uses a heeled bullet, which means that the bullet is the same diameter as the case, and has a narrower “heel” portion that fits in the case. It is one of the few cartridges that are accepted by a large variety of rifles and handguns.