MachIVshooter
Member
Any thoughts on why or if a 7.62 NATO/.308 fmj wound (without yawing) would incapacitate more effectively than an identical shot with a 9mm pistol?
Here's my line of thought - the common knowledge is that the rifle will always be better than a pistol (even if the pistol bullet is larger). If the permanent cavity size is smaller with the rifle round and the temporary stretch cavity (fmj bullet, not yawing) has little if any effect on elastic tissues, it seems that there would be very little difference in the resulting wound.
The bolded part is the flaw in your thinking. The permanent cavity isn't just the diameter of the bullet; It is also that of tissue which was stretched beyond it's elastic limits. The higher velocity of the rifle bullet causes much more stretching, and so you end up with larger cavities of both types.
Hangun permanent cavities tend to be only tissue that was directly contacted by the bullet or secondary projectiles due to the low velocity. The hydraulic pressure created by the much higher velocity of the rifle bullet often creates a wound channel much larger than the projectile itself. It is generally accepted that the point at which we begin to witness the hydrostatic shock component resulting in rifle-type wounds is around 2,000 FPS.