I'll jump in here although I'm sure more qualified people will give a better answer. 1st, any weapon that you can hold in your hand is a pathetic popgun that has limited "stopping" power. The purpose of a bullet is to make holes in things and the "stopping" power comes from either a central nervous system shutdown or by causing hypovolemic shock (loss of blood pressure). Pretty much, any bullet that penetrates deeply enough to accomplish either will stop someone but not necessarily as quickly as Hollywood portrays. FMJ .45 will likely penetrate and could in fact overpenetrate. It also has the advantage of being the most reliable in terms of feeding. I personally carry hollowpoints but I feel comfortable that my guns function reliably with them. I'd carry whatever your gun functions with every time because the important thing is that your gun goes bang.