Exactly how does a .45 'shrink'?
It supposedly "shrinks" (not literally, of course) like I described in the post right before the one that you responded to. The theory is that solid round-nose bullets, due to their streamlined shape, tend to "squeeze" their way through very small holes torn in flesh rather than punching a caliber-sized permanent cavity all the way through. While the entrance wound may be caliber-sized (not sure as I haven't closely examined any myself) because the bullet's velocity is so high at that point, the bullet obviously slows down very rapidly when it encounters flesh and is therefore much less likely to crush every bit that it encounters, pushing most of it out of the way temporarily (part of the temporary cavitation that absorbs the bullet's energy). Supposedly bullets with different shapes such as flat-nose, wadcutter, and semi-wadcutter will use more of their energy to create a caliber-sized permanent cavity rather than a larger temporary cavity. Tests in ballistic gelatin that I've seen appear to bear this out, although gelatin is not exactly the same as flesh, of course. Flesh, however, is generally more elastic and resilient than gelatin, I believe, so take that for whatever it's worth.
Admittedly, this unproven theory depends partly on the real effects of temporary cavitation or rather the lack thereof. The consensus (which proves nothing
) among both forensics experts and gun enthusiasts seems to be that service handgun calibers lack sufficient energy, by a long shot, to cause meaningful damage to flesh outside of the permanent cavity. Kinetic energy makes a nice pattern in gelatin and blows up milk jugs just fine, but (most) flesh is tougher and more elastic as long as there is enough support and total resistance to stretching around it; the latter accounts for exit wounds, which would merely be small holes if the flesh around it were well supported.
What this all boils down to is that some believe or strongly suspect that with round-nose bullets specifically, shot out of handguns, the diameter of the bullet doesn't matter very much (it must count for something but extremely little). Hollow-points and other bullet designs are a different story, but supposedly all round-nose bullets poke tiny holes through most of the target, whatever their caliber. Obviously this runs counter to the popular theory of .45 ACP's pronounced superiority over narrower calibers when using FMJ-RN rounds, such as for military purposes. Both contradictory theories are based on consensus opinions and backed by some anecdotal "evidence" in the field as well, so which is more likely to be correct?
Sorry about the unintentional thread hijack, by the way--sometimes I just respond to what I read.
Nope, to be honest I can't afford to shoot enough of the +$1.00 a round stuff to feel proficient so I compromise.
OK, whatever works for each of us is fine, but I get around this by training with far less expensive FMJ rounds loaded to similar specs. For me that's close enough, but I totally understand why some folks prefer to train with the exact ammo they would use for defensive purposes--it's a personal thing.