Originally Posted by Kai
From what I've read and heard from many others is that hollowpoints will very often blow a nasty hole of an exit wound. The advantage is that it looses so much energy, it will usually not pass through the wall behind the person you shoot at, thus making it good for home defense.
It's not uncommon for a JHP to pass through the assailiant, however it's not nearly as common with an FMJ.
Furthermore, if it does; as you stated it creates a "nasty hole of an exit wound" which is a lot more capable of stopping and inducing blood loss of the said aggressor, than an FMJ which would punch a 1/4" hole straight through. As I read oso neatly on a bullet test site, "We want to punch a hole in the hydraulics of the person, to induce blood loss and to stop blood flow to the brain so they can no longer pose a threat."
It's not so much because of their inability to penetrate walls and things of that nature that makes JHP's so nice, it's because of their ABILITY to rip apart flesh much larger than the size of the round itself.