The 22 Long Rifle or simply 22 LR (metric designation: 5.6×15mmR) is a long-established variety of 22 caliber rimfire ammunitions originating from the United States. It is used in a wide range of rifles, pistols, revolvers, smoothbore shotguns, and submachine guns.
In terms of units sold it is by far the most common ammunition in the world today. Common uses include hunting and shooting sports. The 22 Long Rifle is effective at short ranges and has little recoil making it ideal for training.