07-19-2014, 03:21 AM
The papers in the subsequent links help explain a little bit but the differences in permanent wound channel sizes between the bullet design classes was empirically derived.
The methodology looks at the size (area) of the permanent wound channel compared to the animal's weight. The required relationship was essentially established by archeologists working to understand why mesolithic (5,000 10,000 years ago) hunter's arrowheads had particular sizes.
Traditional lead core bullets tend to expand quickly but lose weight starting right after impact resulting in less penetration than might otherwise be the case. The copper alloys in lead-free bullets tend to be very ductile allowing them to retain most or all of their initial weight. They also tend not to expand as much which allows them to penetrate rather deeply compared to lead-core expanding bullets. Logically, the wound channel must first be deep enough, with the actual diameter also an important but secondary consideration.
The methodology looks at the size (area) of the permanent wound channel compared to the animal's weight. The required relationship was essentially established by archeologists working to understand why mesolithic (5,000 10,000 years ago) hunter's arrowheads had particular sizes.
Traditional lead core bullets tend to expand quickly but lose weight starting right after impact resulting in less penetration than might otherwise be the case. The copper alloys in lead-free bullets tend to be very ductile allowing them to retain most or all of their initial weight. They also tend not to expand as much which allows them to penetrate rather deeply compared to lead-core expanding bullets. Logically, the wound channel must first be deep enough, with the actual diameter also an important but secondary consideration.