the .45 will have more knock down power. Thats simple to determine. Having said that, with alot of todays loads and bullets, the gap between the rounds is getting closer IMO. I say stick with what you shot the best. I have said before, i have seen people at the range get sold on a .45 only to discover they can't hit a paper target 5 yards away because they were sold a gun or caliber that didn't fit them.