Ok! Heres the argument. The high velocity bullet deforms going in and hits something and ricochets around hitting three or four spots before coming to rest. Basically a blender action. Larger calibres tend to go straight and stop or exit giving only one wound. I've heard of head shots where the .22 went around inside the skull and didn't kill because it was running between the brain and the skull. But body shots, even off center, wind up ricocheting around until something vital is hit.
From my deer hunting experience where you get shot is the most important. I believe in "one shot one kill" or I don't take the shot. I hate tracking a deer for miles. Even a deer with his heart blown away can still make it a good 200 yards.
Hanguns fire at slower velocity than rifles. So the argument about velocity would only work if you are talking about a .22 rifle. The bigger the handgun caliber the better.
Here's some info from wikipediaHangun effectiveness and .22 caliber