The .22 Hornet or 5.6×36mmR Hornet is a varminting, small-game hunting, survival and competition centerfire rifle cartridge commercially introduced in 1930. It is considerably more powerful than the rimfire .22 WMR and the .17 HMR, achieving higher velocity with a bullet twice the weight of the .17 HMR bullet. The Hornet also differs significantly from these in that being a centerfire cartridge makes it reloadable, and thus more versatile. It was the smallest commercially available .22 caliber centerfire cartridge until the introduction of the FN 5.7×28mm.

The .22 Winchester Magnum Rimfire, also known as the .22 WMR, .22 Magnum, .22 WMRF, .22 MRF, or .22 Mag, is a rimfire cartridge. Originally loaded with a bullet weight of 40 grains (2.6 g) delivering velocities in the 2,000 feet per second (610 m/s) range from a rifle barrel, .22 WMR is now loaded with bullet weights ranging from 50 grains (3.2 g) at 1,530 feet per second (470 m/s) to 30 grains (1.9 g) at 2,200 feet per second (670 m/s).