I just had an opportunity to watch the guys at Hornady run their Critical Duty ammo and a bunch of "audience" ammo through the FBI protocol test (bare gel, cloth, plywood, wallboard, steel, and glass) through FBI formula gelatin and came away rather impressed that companies can design ammo that can perform pretty evenly in jello after passing through all the different barriers. The other impressive thing was that the variations in results between 9mm, .40 and .45 were rather negligible. So, yeah, for self defense, all things being equal, the ammo you shoot the bestest and the fastest would be the better ammo to use.
None of the ammo other than the Critical Duty was as consistent, but a lot of it was close enough for me. I was fine with .45 230 grain Gold Dots fired from service length barrel and an XDs 3.3" although they technically did not "pass" all the FBI tests. Same with .40 180 grain Gold Dots out of a Glock 35. I also was fine with the standard velocity 9mm 124 Gold Dot out of a Glock 17 and a 9mm 147 grain Winchester XST out of a service length barrel, although they technically did not "pass" all 6 tests. I also was fine with a standard velocity 9mm 124 Gold Dot fired out of a S&W Shield on the clothed gelatin test, which is a standard self defense scenario.
Deer, elk, lions and bears are a different story, and wallboard, steel and windshield barrier tests don’t sound too relevant, nor do concerns about overpenetration.
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