Twist Rate: The twist rate refers to the rate of twist in the barrel’s rifling, which determines the stability of the projectile in flight. Common twist rates for AR-15 barrels include 1:7, 1:8, or 1:9. The twist rate is usually specified by the manufacturer and may be optimized for specific bullet weights or applications.
Profile: The barrel profile refers to the shape and dimensions of the barrel. Common profiles for AR-15 barrels include the government profile, lightweight profile, and heavy profile. Each profile offers different benefits in terms of weight, balance, heat dissipation, and compatibility with different handguards or accessories.