If I were an intruder in your home, and you defended yourself with 115gr 9mm+P JHPs, it would definitely ruin my day.
Personally, I like heavy subsonic 147gr 9mm JHP for my carry pistol. It is true that 147gr 9mm rounds were not originally meant for pistols (apparently they were meant for submachine guns) and that the early 147gr JHP bullets often failed to expand due to their low speed. Modern bullet design has made the good 147gr hollowpoints reliable expanders. Tests in bare and denim-covered gelatin show good penetration and consistent expansion for reputable JHPs like Remington Golden Sabers, Corbon DPX, Federal Hydrashoks, Speer Gold Dots, and others. Even the low-cost Winchester USA (White Box) 147gr JHP rounds performed well in the tests I've seen.
115gr +P JHPs and 147gr subsonic JHPs are on opposite ends of the 9mm spectrum. The argument between "fast and light" and "slow and heavy" will go on for a very long time. Your "fast and light" bullets have the advantage of being fast enough that they'll probably have no trouble expanding if they hit your target, but don't let people tell you that lighter is better for home defense because of the decreased risk of overpenetration.
Don't get me wrong. A 115gr bullet may stop with less resistance than a 147gr bullet, but don't let that fact make you get careless. I've actually tried shooting various .380 and 9mm loads into a simulated interior wall. I built a small section of wall using 2 layers of 1/2 inch sheetrock separated by 2x4 studs. My 95gr .380ACP FMJ, 102gr .380ACP Golden Sabers, 115gr 9mm FMJ, 124gr 9mm JHP, 124gr 9mm+P JHP, 147gr 9mm FMJ, and 147gr 9mm JHP all penetrated both sides of the wall and buried themselves in a mound of dirt located 6 feet behind the simulated wall.
This wasn't a scientific test. I don't know how much energy each bullet carried after passing through the wall. All I know is that they all went straight through both sides of the wall and disappeared into a mound of dirt.
I wouldn't want that mound of dirt to be somebody I loved. We talk about shot placement being the most important factor with in ANY home defense situation, and I couldn't agree with that statement more, but it's a double sided coin. You don't just have to become proficient enough to put your shots on target. You also have to be responsible enough to think about your backstop. That's one more reason to become proficient with your carry weapon. If you hit your intended target with reputable defensive ammunition, it's very likely that the bullet will expand and slow significantly inside the attacker or intruder's body. If the bullet does manage to leave your target's body, it will be deformed, and it will be carrying significantly less energy to hurt people and things beyond your target.
