Quick Answer
A higher barrel twist rate in the .280 AI rifle can improve accuracy by stabilizing longer, heavier bullets in flight, but excessive twist rates can lead to bullet instability and reduced accuracy.
Twist Rate Optimization for .280 AI
The .280 Ackley Improved (AI) cartridge is a high-velocity, long-range cartridge that benefits from a proper barrel twist rate to maintain accuracy. A general rule of thumb is to use a barrel twist rate of 1 turn in 7 inches (17.8 cm) or 1 turn in 8 inches (20.3 cm) for bullets weighing 150-160 grains (9.7-10.4 grams) at a velocity of approximately 2,900-3,000 feet per second (882-914 m/s). However, for heavier bullets, a higher twist rate may be necessary.
Effects of Over- and Under-Twist
A barrel twist rate that is too low for a given bullet weight can cause the bullet to destabilize in flight, leading to reduced accuracy and increased wind drift. Conversely, a barrel twist rate that is too high can also cause bullet instability, particularly if the bullet is not designed to handle high spin rates. For example, a 1,500-grain (96.8-gram) bullet that is stabilized at a twist rate of 1 turn in 7 inches (17.8 cm) may become unstable at a twist rate of 1 turn in 5 inches (12.7 cm) or faster.
Choosing the Right Twist Rate for .280 AI
To determine the optimal barrel twist rate for your .280 AI rifle, consult the manufacturer’s specifications for the bullet you are using, or consult with a firearms expert. It’s also essential to test the rifle with different bullet weights and twist rates to determine the optimal combination for your specific application.
Find more answers
Browse the full Q&A library by topic, or jump back to the topic this question belongs to.