If you have ever browsed rifle barrels, you have seen numbers like 1:7, 1:8, or 1:9 in the specs. That is the barrel twist rate, and it has a major influence on whether your favorite bullet flies straight or tumbles. This guide explains what barrel twist rate is, how it works, and how to match it to your ammunition. What Is Barrel Twist Rate? Barrel twist rate describes how quickly the rifling inside a barrel makes the bullet spin. Rifling is the set of spiral grooves cut into the bore. As a bul …