.22 caliber

The 5.6 mm caliber or .22 caliber, is a small, extremely common size of ammunition, fitted to firearms with a bore diameter of 5.6 mm (0.22 in). It is the most common bore for rimfire ammunition, and has gained popularity in the air gun discipline as a hunting/field target/Hunter Field Target pellet caliber.

5.6 mm caliber rimfire variations include:
 * .22 Long Rifle (LR), the most common cartridge type of this caliber, often referred to simply as ".22 caliber"
 * .22 BB (Bulleted Breech Cap)
 * .22 CB (Conical Ball Cap)
 * .22 CB cap, an American rimfire cartridge
 * .22 Long, same length, but lighter bullet than .22 LR
 * .22 Extra Long, an American rimfire rifle and handgun cartridge
 * .22 Short, used mostly in pocket pistols and mini-revolvers
 * .22 Winchester Rimfire, an American rimfire rifle cartridge
 * .22 WMR, (Winchester Magnum Rimfire) a cartridge that is longer and more powerful than a .22 LR
 * .22 Winchester Automatic, an American rimfire rifle cartridge

5.6 mm centerfire cartridges include:
 * 5.56×45mm NATO, an intermediate cartridge widely used in modern sporting rifles
 * .22 Accelerator, a special loading of the .30-30, .308, and .30-06 cartridges that is manufactured by Remington
 * .22 Eargesplitten Loudenboomer, a cartridge for a rifle
 * .22 Hornet, a powerful variation, also known as 5.6×35R mm 5.728mm
 * .22 Remington Jet, an American centerfire revolver and rifle cartridge
 * .22 BR Remington, a wildcat cartridge commonly used in varmint hunting and benchrest shooting
 * .22 Savage HP, a.k.a. 5.6×52R, .22 Savage Hi-power, .22 Imp, a cartridge similar to the 22 Hornet introduced by Savage in 1912
 * .22 Spitfire, an American rifle cartridge
 * .22 PPC, a firearm cartridge used primarily in benchrest shooting
 * .22 TCM (a.k.a. .22 Micro-Mag), a 9mm diameter case necked to a .22 caliber bullet and designed to load into standard 9mm magazines; currently proprietary of Rock Island Armory and accommodating of that company's pistols and carbines also sold with 9mm barrel swap kits.