Sizing is a function of toughness. Final boolit size desired is the dynamic fit of the boolit to freebore-leade when the gun is fired until when the boolit passes the max pressure point. After that the barrel should be tapered to maintain a smooth pressure drop. This section usually occurs too fast to visually see on a scope when using a single "cheap" tranducer. Besides, who says the gun has a perfect crown? Usually, only BR guns do (or did in my case). ... felix
Sharper the max pressure point, the faster the whip amplitude. Faster the whip amplitute, the more important the boolit leaves the muzzle when the boolit is moving the slowest, hopefully not at all. ... felix