[Mariner]

" I’m thinking it was 9mm. A .40 would have."

Both should pop through, no problem.

9mm routinely passess through a 4x4 post...hell, I've seen 124gr hollow points pass through a 5inch green tree trunk. In fact one of the old-school gripes on the round is that it pops through too easily...which is a naive perspective.

[SkyDancer]

So the guy must have been huge for no bullets to come out of his back.