+1 for this. Any round will penetrate at least one wall, and any round sufficient for self-defense will penetrate multiple walls. You need to know what angles in your house are safe to shoot and which are not--ie make sure a miss doesn't go zipping into an occupied bedroom.Excaliber wrote:Careful here. LE tests show that the light and fragile .223 stops more quickly in less wallboard than the standard LE pistol calibers. 9mm zips through wallboard just fine.
.223 may be less likely to continue going once it goes through a bad guy as compared to pistol rounds--this is due to the velocity difference. The light, fast .223 bullet is famous for tumbling and fragmenting inside the body. The heavier, slower pistol bullets won't do this and thus may be more likely to exit. That risk can of course be reduced by using quality hollowpoints, but most entry teams have moved away from pistol-caliber SMGs to rifle-caliber carbines for this reason (plus other advantages).