The .222 Remington, which is also known as the Triple Deuce/Triple Two/Treble Two is a centerfire rifle cartridge. Introduced in 1950, it was the first commercial rimless .22 (5.56 mm) cartridge made in the United States. As such, it was an entirely new design, without a parent case. The .222 Remington was a popular target cartridge from its introduction until the mid-1970s and still enjoys a reputation for inherent accuracy. It remains a popular varmint cartridge at short and medium ranges with preferred bullet weights of 40-55 grains and muzzle velocities from 3000-3500 fps.
The .222 Remington was introduced in the Remington Arms Model 722 bolt action rifle. Factory rifles often produce groups of one minute of arc (0.3 mrad) or less with no tuning. The accuracy and flat trajectory of the cartridge resulted in the adoption of the round for varmint and benchrest rifles. The faster .220 Swift and .22-250 Remington provided more reach than the .222 Remington. These larger cartridges have more power (roughly 50 percent more) than the .222, but also more muzzle blast and barrel erosion.
The .222 Remington is popular in Europe where it is known as 5.7×43. Sako was one of the first European makers to introduce .222 Remington rifles and cartridges, and German and Austrian hunters quickly adopted the .222 Remington for hunting smaller deer sized game.