Rifling

Rifling consists of spiral grooves cut into the inside of a barrel of a gun.^[1] It causes the bullet or projectile to spin as it flies through the air. This greatly improves the accuracy of the bullet over longer distances.^[2] The first muskets to use this technology were called rifles.^[2] Barrels are rifled using a left or right twist. The number of turns per inch is called the "twist rate". These are expressed as a ratio. For example, a 1:7 twist means the bullet will turn once for each seven inches of barrel length. As a general rule, the heavier the bullet, the higher the twist rate.^[3]

1. ↑ "rifling". Dictionary.com, LLC. Retrieved 28 July 2016.
2. ↑ ^{2.0 2.1} "Early Firearms History". The Firearms Guide. Archived from the original on 1 July 2016. Retrieved 28 July 2016.
3. ↑ Keith Wood (23 December 2013). "How to Pair Barrel Twist Rates with Bullets". Outdoor Sportsman Group. Retrieved 28 July 2016.