Now, when talking about shooting people and/or animals the skin will stretch out and you probably wont get a WOUND that is that same diameter but that is going to be the same with any bullet.
That's pretty much what I meant, yes. And you actually can observe a similar effect in paper; wadcutters make a nice, clean hole, while roundnoses and hollowpoints tend to completely "punch out" a less-than-caliber width hole, then tear the rest of the way through the paper.
Elastic tissues are about the same way, except the stretch around the bullet rather than tearing, resulting in a smaller hole.
Wadcutters, on the other hand, generally will crush a totally caliber-width hole, or very nearly so, for their entire penetration depth.
The mechanism involved in making a hole is
pressure not "energy" as most would have you believe. A rounded bullet exerts its highest pressure on the very tip, and a gradually lower pressure the further from the tip you get. The end result is that near the tip, where pressure is very high, tissues get crushed and disintigrated; but closer to the edges, where pressure is lower, tissue is able to flow around the bullet undamaged.
As momentum is shed due to
drag (not "energy transfer"), the velocity goes down, as does the pressure; as a result, the "pressure gradiant" across the face of the bullet changes so that only a narrower and narrower portion of the bullet has enough pressure to crush a hole (due to the ogive's sloping surface), until finally velocity is so low that none of it can, and the bullet stops altogether.
A flat faced wadcutter, however, exerts nearly equal pressure with its entire frontal surface; if the edge is sharp enough, it even exerts more pressure around the sides than the middle! The result is a caliber-width hole for the entire length of penetration; it loses velocity still, of course, but instead of the "pressure gradiant" getting narrower, the pressure on the entire face uniformly goes down (it starts out well above what is necessary to crush tissue, at handgun velocities), until pressure is too low to make a hole, and the bullet stops.
In case I explained that inadequately (wouldn't be the first time!) here's a nifty graphic that hopefully clarifies what I just said.