Rifling

Rifling is the helical grooving cut inside a gun barrel to spin the projectile, steadying its flight and making it more accurate. Its inventor is not known: straight 'soot grooves' were cut in small arms from at least 1480, and among the earliest recorded spiral-grooved barrels are those of the Vienna gunsmith Gaspard Kollner in 1498 and of Augustus Kotter of Nuremberg in 1520. Because the grooves had to be engraved by hand, rifled guns were at first used mostly by wealthy hunters, and they became common only in the mid-19th century; the first practical military rifled weapons were breech-loaders such as the Queen Anne pistol.