Quick Answer
Copper bullets' performance may vary with twist rate, as a higher twist rate can be required to stabilize the bullet's aerodynamic characteristics, particularly for longer or more complex bullet shapes.
Twist Rate Considerations
When choosing a twist rate for copper bullets, consider the bullet’s length, weight, and profile. For example, a 1:8" twist rate is often sufficient for shorter, lighter copper bullets like the 90-grain Barnes TSX. However, longer or heavier bullets, such as the 150-grain Sierra MatchKing, may require a higher twist rate, like 1:7" or 1:6.5", to maintain stability and accuracy.
Bullet Design and Twist Rate
Monolithic bullets, which have a solid copper construction, can be more sensitive to twist rate than jacketed bullets. This is because the copper material can be more prone to deformation and in-flight oscillation. To mitigate this, look for bullets with a streamlined profile and a well-designed ogive, which can help reduce the bullet’s aerodynamic drag and improve stability at longer ranges. A good rule of thumb is to choose a twist rate that is at least 1:7" for bullets weighing over 120 grains.
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