.222 Rem. Mag.

The .222 Remington Magnum (also known as the 5.6x45mm) is a centerfire rifle cartridge that was introduced in 1958 by the Remington Arms Company. It is a magnum version of the .222 Remington cartridge, and was designed to offer improved ballistics and longer range compared to its predecessor.The .222 Remington Magnum uses a bottlenecked case with a bullet diameter of 5.7mm and an overall case length of 44.5mm. It typically fires a 50-55 grain bullet at a muzzle velocity of around 3,000 feet per second, delivering flat trajectory and high accuracy at medium to long ranges.The cartridge enjoyed some popularity among varmint hunters and target shooters in the 1960s and 1970s, but has since been largely supplanted by other cartridges such as the .223 Remington and .22-250 Remington. Nonetheless, the .222 Remington Magnum remains a capable and accurate cartridge that is still in use by some hunters and enthusiasts.