Definitions for ".22 Long"
Long is a variety of .22 caliber (5.56 mm) rimfire ammunition. The .22 Long is the second oldest of the surviving rimfire cartridges, dating back to 1871, when it was loaded with a 29 grain (1.9 g) bullet and 5 grains (0.32 g) of black powder, 25% more than the .22 Short it was based on. It was designed for use in revolvers, but was soon chambered in rifles as well.