Air Rifle Pellets vs. Slugs — Optimizing Barrel Turn Rate

This article is from the Applied Ballistics’ Facebook Page Air Rifle Pellets vs. Slugs — Twist Rate Test Initial radar testing shows a fascinating stability trend: drag is minimized when pellets are used in barrels with a slower twist, whereas drag of slugs for slugs has a faster spin. Drag/BC consistency is best when drag (BC) is minimized. Below are test results for.300 calibre 44.5 grain slug and.300 calibre 44.8 grain pellet, both fired from an air gun at around 800 FPS. It’s great to see that the measurements confirm what experienced air rifle shooters have told us. Why is fast twist better for slugs but bad for pellets, and vice versa. Air rifle pellets with skirts are mainly drag-stabilized and not spin-stabilized. They don’t require much spin to fly forward. The skirt catches air like the fins on a rocket. The pellets will only become unstable if you spin them faster. After looking at these data, I would suggest trying a slower twist for the pellets. Perhaps a 1:60″ (one turn every 5 feet) or even a 1:120″. Slugs are spin stabilized, so it makes sense that more spin would suppress yaw while maximizing BC. According to these results, the slug reaches maximum stability/BC at the 1:22′ and the 1/18” does not provide any further benefit. These are only preliminary findings. We’re excited to explore more in the coming weeks. Click here to view our latest Air Rifle Projectile Testing, including the full 8-minute video. The Science of Accuracy in Air Rifle Testing Part 1 Video