Here are Dr. Gary Roberts thoughts on .380 ACP from the terminal ballistic section on m4carbine.net
http://www.m4carbine.net/showthread.php?t=19914
Handguns chambered in .380 ACP are small, compact, and generally easy to carry. Unfortunately, testing has shown that they offer inadequate performance for self-defense and for law enforcement use whether on duty as a back-up weapon or for off duty carry. The terminal performance performance for self-defense and for law enforcement use whether on duty as a back-up weapon or for off duty carry. The terminal performance of .380 ACP JHP's is often erratic, with inadequate penetration and inconsistent expansion being common problems, while .380 ACP FMJ's offer adequate penetration, but no expansion. All of the .380 ACP JHP loads we have tested, including CorBon, Hornady, Federal, Remington, Speer and Winchester exhibited inconsistent, unacceptable terminal performance for law enforcement back-up and off duty self-defense use due to nadequate penetration or inadequate expansion. Stick with FMJ for .380 ACP or better yet, don't use it at all. The use of .380 ACP and smaller inadequate penetration or inadequate expansion. Stick with FMJ for .380 ACP or better yet, don't use it at all. The use of .380 ACP and smaller caliber weapons is really not acceptable for law enforcement use and most savvy agencies prohibit them While both the .380 ACP and .38 sp can obviously be lethal; the .38 sp is more likely to incapacitate an attacker when used in a BUG role. BUG--Infrequently used, but when needed, it must be 100% reliable because of the extreme emergency situation the user is dealing
http://www.m4carbine.net/showthread.php?t=19914
Handguns chambered in .380 ACP are small, compact, and generally easy to carry. Unfortunately, testing has shown that they offer inadequate performance for self-defense and for law enforcement use whether on duty as a back-up weapon or for off duty carry. The terminal performance performance for self-defense and for law enforcement use whether on duty as a back-up weapon or for off duty carry. The terminal performance of .380 ACP JHP's is often erratic, with inadequate penetration and inconsistent expansion being common problems, while .380 ACP FMJ's offer adequate penetration, but no expansion. All of the .380 ACP JHP loads we have tested, including CorBon, Hornady, Federal, Remington, Speer and Winchester exhibited inconsistent, unacceptable terminal performance for law enforcement back-up and off duty self-defense use due to nadequate penetration or inadequate expansion. Stick with FMJ for .380 ACP or better yet, don't use it at all. The use of .380 ACP and smaller inadequate penetration or inadequate expansion. Stick with FMJ for .380 ACP or better yet, don't use it at all. The use of .380 ACP and smaller caliber weapons is really not acceptable for law enforcement use and most savvy agencies prohibit them While both the .380 ACP and .38 sp can obviously be lethal; the .38 sp is more likely to incapacitate an attacker when used in a BUG role. BUG--Infrequently used, but when needed, it must be 100% reliable because of the extreme emergency situation the user is dealing