One of the big name gun magazines recently ran a article comparing different caliber defensive loadings, including the 380. They found the 380 95 gn fmj ball ammo penetrated the deepest. They also found that lots of the 380 defensive loadings using expanding slugs did not penetrate well at all. Some opened well but did not penetrate, some penetrated but did not open well. Some, like the cor-bon loads (two I believe) I just dismissed as too fast, too light, and not heavy enough to penetrate to a depth far enough to get the job done. I have also found from prior experience that fmj bullets will not open up or expand if you drill a hole in the nose - the nose is usually thick enough on a fmj slug to prevent deformity during cycling and this design simply keeps it from opening whether you get into the lead core or not.
The 380 has been and continues to be one of my favorites. Used properly with effective shot placement the cartridge will get the job done. I have often felt and am confirmed by test results, including my own, that the fmj bullet penetrates the furthest and will effect the most damage by doing so - all the defensive shooter needs to do is place his shots properly. One nice thing about the 380 and magazines that hold 6-8 rounds is that the extra mags are so lightweight, even when full, that the extra one in your pocket doesn't weigh you down. But, as with any defensive pistol, you need to practice your presentation and shot placement, and if it takes 3 shots to knock down a bad guy with a 380, then practice a 3-shot defense. Truly, I have never ehard of anyone getting up after 3 shots of 380 to the chest and btw, testing the 380 on 2x4s or other hard surfaces is not a good test as the 380 is not a hard target caliber. Get some 1 gallon milk cartons (empty of course), fill'm with water and cap them, line up half a dozen full ones, tape them together with duct tape and fire one round into them from a dead on position and see how far they penetrate. If they go into 3 or more they are penetrating as deeply as some of the 38 spl defensive loadings of the day. jmtcw.