If your ammo is exiting the target, you’re doing it wrong. :)

Shoulda compared those little tiny holes to even a .410 loaded with almost anything.

And there ain’t hardly no exit wounds, because all those little Bee-Bees are all inside sting-stinging you to death.

Which is why you should carry a pistol grip short shotgun.

Plus, I’m not that great a shot and expect I’d get worse if stressed or frightened.

Plus, plus, I once got hit by one itty bitty #6 bird shot, and it immediately distracted my attention from all other matters.

An exit wound is a likely lawsuit (hitting someone else or someone else’s property, so there should be no exit wounds. Defensive ammo is made to penetrate and expand and not exit.

A 9mm round is ballistically the same or better than a .45 because supersonic wound damage is better than subsonic (.45) wound damage. Always carry 9mm.

Over at Buckeye Firearms Assoc., Greg Ellifritz has published an analysis of handgun stopping power:

https://www.buckeyefirearms.org/alternate-look-handgun-stopping-power

He shows that if deterrence is the goal any caliber works, .22 lr equal .45 acp. The pain due to a gun wound is severe enough to deter almost anyone.

Of course, someone shot with a .22 lr will likely just run away, whereas someone shot with a .45 is dead.

Of course it is not the size of the hole going out, but the volume of damage done on the inside.

And while the .22 has narrow tube of damage, it often has a very long tube due to pinging around inside, this also increases the likelihood of hitting something critical.