22 WMR

Winchester introduced the cartridge they named “22 Winchester Magnum Rimfire” in 1959. The round is commonly abbreviated as “22 WMR” but it’s just as often shortened to “22 Mag.” So, to be sure, if you order 22 WMR ammo for your 22 Mag firearm – or vice versa – you are doing the right thing. However, this caliber should never be used in a firearm chambered for 22 Long Rifle or 22 LR.