 The .223 designation is a reference to the popular .223 Remington.It is currently claimed to be the fastest production .22 caliber round in the world with muzzle velocities as high as 4,600 feet per second (1,402 meters per second), but this is not completely true.The .220 Swift still holds the record as the fastest .22 caliber centerfire cartridge with a published velocity of 4665 fps using a 29 grain projectile and 42 grains of 3031 powder.