Muzzle velocity

Muzzle velocity is the speed of a projectile (bullet, pellet, slug, ball/shots or shell) at the moment it leaves the end of a gun's barrel (i.e. the muzzle). Firearm muzzle velocities range from approximately 120 m/s (390 ft/s) to 370 m/s (1,200 ft/s) in black powder muskets, to more than 1,200 m/s (3,900 ft/s) in modern rifles with high-velocity cartridges such as the .220 Swift and .204 Ruger, all the way to 1,700 m/s (5,600 ft/s) for tank guns firing kinetic energy penetrator ammunition. To simulate orbital debris impacts on spacecraft, NASA launches projectiles through light-gas guns at speeds up to 8,500 m/s (28,000 ft/s).

Several factors, including the type of firearm, the cartridge, and the barrel length, determine the bullet's muzzle velocity.

Projectile velocity

For projectiles in unpowered flight, its velocity is highest at leaving the muzzle and drops off steadily because of air resistance. Projectiles traveling less than the speed of sound (about 340 m/s (1,100 ft/s) in dry air at sea level) are subsonic, while those traveling faster are supersonic and thus can travel a substantial distance and even hit a target before a nearby observer hears the sound of the weapon being fired. Projectile speed through air depends on a number of factors such as barometric pressure, humidity, air temperature and wind speed.

A 1-gram (15.4-grain) projectile was accelerated to velocities exceeding 9,000 m/s (30,000 ft/s) at Sandia National Laboratories in 1994. The gun operated in two stages.