re: frangible or hollow point?

JJ, Don't worry too much about excessive penetration of a 223 Rem when shot in a house if you're using the appropriate bullet. A number of studies have shown that, depending on the bullet used, the 223 Rem fired from a rifle intot sheet rock penetrates MUCH less than many handgun rounds. In this study, the 223 Rem HP and SP loads penetrated much less sheet rock than did the JHP 40 S&W. Part of the deep penetration of the JHP was due to the HP filling getting plugged up w/ sheet rock, effective changing the bullet in to a round nose.
LINK

Here's another study:
LINK

Some of the conclusions from the second study:

"Moving away from rifle rounds takes us from fascinating discoveries into the realm of mythbusting. Handgun rounds, for instance, may penetrate less than rifle rounds--but only if the rifle rounds in question are full-power ball ammo. The relatively slow speed and heavy weight of handgun bullets make them a poor choice for limiting interior wall penetration, which is why professional door-kicker types have abandoned pistol-caliber submachineguns in favor of .223 carbines.


Shotguns may be the most powerful repeating shoulder-fired gun available, but when stoked with 00 buckshot they are certainly not a low-penetration option. In fact, the way the pellets spread out after passing through intermediate barriers makes the safety of anyone or anything within three rooms of a shotgun blast highly dubious."