In many loadings you have to go to a "+P" loading tohave more "power"in the .45 ACP. I do not want to be on the business end of either one. Go to Winchester, Federal, and others and compare the ballistics of the two.Do a google search forDoubleTap ammo as they produce some excellent self defense ammo.

I actually find that the .40 S&W has a snappier or sharper recoil than the .45ACP. I personallyam a little more accurate with my .45ACP than I am with mytwo .40 S&W's.I don't think you can go wrong with either choice. I also don't think you would go wrong with a 9mm either.