Your one round knock down power theory is obsolete if you miss your target, I'd rather be able to hit my target 5 times with a 9 and get good results, then miss with a .45. A .45 is NOT a end all be all weapon, it never has been and never will be.
( Amen) RJ some of these .45 guys are just full of them self with there 1 shot wonder magic .45 cal. bullets. We have done some nonscientific testing in the back yard at 7 to 10 yds with .380, 9mm, .40 and .45’s with denim, catalogs, phone books and drywall attached to 2x6’s and a multitude of different PD ammo and a stack cement blocks with FMJ and PD when we where finished everyone especially the .45 and .40 guys where surprised at the damage and penetration done by all 4 calipers. No one wanted to jump up and take a hit even from the lowly .380