Doc,
Assume the numbers below come out of a properly done IWBA standard 4 layer denim test in properly calibrated ballistic gelatin. I'm intentionally not dealing with barrier penetration issues (auto glass, steel, wallboard, etc.)
Take two 9mm rounds. Both penetrate past 12". For the first hypothetical, they penetrate equally One expands to .5", the other expands to .6" I look at the math of this, calculate the frontal areas of the two bullets, and see that the larger bullet has a 44% larger frontal area. (Note, I'm taking frontal area as a simple circle to calculate area based on diameter.) I take this as giving it 44% advantage in destroyed tissue, and figure this most have some significant increased effect on incapacitating capability. Is this thinking correct, or am I missing something? If it's the latter, what am I missing.
In the second hypothetical, everything is the same as the first one except penetration. The bullet that expands to .6" will penetrate to 13" While the bullet that expands to .5" penetrates to 16". If I now take the frontal area and multiply by penetration, I get crush cavity volume. The bigger bullet still has an advantage here by about 17%. But the other factor in penetration is that the deeper penetrating round might hit something the shallower penetrating round wouldn't. But given the fact that both meet the minimum standard, which, if either, would have a better chance of a quick incapacitation?
Let me know what you think. Thanks.