switched to a .45

[Rastoff]

What's the logic behind using FMJ in a self defense handgun? You need both penetration AND expansion to damage body tissue. Clean pass throughs won't do as much damage.

While this statement is mostly true, there is sound logic for using hardball ammo.

First of all, there's no guarantee that a JHP will expand. I saw one story where a guy accidentally shot himself with a .38JHP. It went through his thigh and embedded in his other calf. The bullet never expanded even though the conditions for expansion were perfect.

Self defense with a gun is about transfer of energy. You want to transfer all the energy of the bullet to the bad guy. Any bullet that goes through didn't transfer all its energy.

Further, your gun has to work. Therefore, you want the most reliable ammo. FMJ has a proven record for that.

A .45 FMJ or Lead Wad Cutter(LWC) is the best compromise. A 9mmJHP might expand, but a .45 won't get smaller. There is much less chance of shooting through with a .45FMJ than there is with a 9mmFMJ.