look, any load that has enough energy to put down an assailant has enough energy to punch through several standard sheetrock and 2x4 walls. conversely, any load that does not have enough energy to exit your house and enter your neighbor's house will not reliably stop your adversary. as long as you use modern jacketed hollow point or ballistic tip bullets or no smaller than #4 buck and HIT your target, the danger to your neighbors should be minimal. you should not rely on handguns for home defense but as long as there are no kids in the house, i understand the reasoning of having several peashooters laying around. a rifle or shotgun should be your defensive weapon. i use an ar-15 with 50 jhps. this load gives very respectable terminal ballistics, outperforming almost any handgun round, the jhp reliably expands and/or fragments with deep enough penetration to destroy vital organs but not so much as to be likely to overpenetrate. the round has the least wounding potential left over after traveling through intermediate obstacles in both the fbi and box o' tests in relation to .45 jhp, 9mm jhp, .40 jhp and 12 ga buck. the least wounding potential is still easily fatal, however. a rifle or shotgun make hits easier and THAT is how you avoid hurting your neighbor.
you live in a much more conservative state than ny so i wouldn't worry too much about litigation. besides, you have to survive to be sued, right? i realize that suing victims after the fact works in other states, but it doesn't carry much weight in az. if it happens bite the bullet, take out a loan and hire a lawyer. he will soundly beat the crap out of them in court and you will countersue to recover court and attorney fees with a little on top for the stress of the whole court process. you will likely win your countesuit if their original suit is shown to be the fraud that it is. remember, while this is entirely possible, it supposes that someone does, in fact, break into your home, that you miss enough times to make it statistically probable that your neighbor gets hit (read: wild, unaimed shots, magazine after magazine) AND you somehow survive the encounter. come to think of it, maybe you should be sued because the only way for you to hit your neighbor is to miss your intended target and it is still statistically improble unless your hosing rounds off.
use a rifle in 5.56 mm, load it with 50-55 gr jhps, jsps, or ballistic tips and HIT your target.
