5.56mm (M855) vs 9mm JHP

Question
Probably a stupid question, but I have an argument with a fellow Airman about this. Which would do more damage at point blank range (within 25 ft): a 5.56mm NATO (M855) fired from an Colt M4 or a 9X19mm JHP (hollowpoint) fired from a Beretta M9? Both are fired into the sternum and no body armor is used. He says the 9mm would because although it is a pistol round, the hollowpoint is designed to "spread" on impact, thus imparting more energy on the body and the 5.56mm would just whiz through with minimal damage. I say its the 5.56mm because hollowpoint or not, the round hitting the sternum at 3100 f.p.s. is going to cause the bullet and breastplate to shatter, forcing debris into the chest with plenty of velocity. Any help would be appreciated.

Answer
Well, Jay, if you had anything riding on this bet, you just won. 5.56 probably won't generate that velocity out the 14.5" barrel of the M4, but it will be more than 2.5 times faster than a 9mm out of any pistol.

Because the 5.56 is so light, as soon as it hits a medium, it stops spinning. The gyroscopic action is what keeps that light pointy tip facing forward. As soon as it stops spinning, it wants the fat heavy end to take the lead. The 5.56 is designed with a thin jacket to be weak at the cannelure, and it will begin to come apart and fragment there, transferring a hellish amount of kinetic energy into the medium.

You only need to look at the FBI statistics on shootings to know that you're right. They vary from year to year, but basically it goes like this. Of all those people shot with handguns, about 90% of them survive their wounds (with little difference concerning where or how many times or at what distance someone is shot). When it comes to shootings with a rifle, however, the figure is almost the inverse - only about 10% of those shot anywhere with any kind of rifle survive.

It's why any self-defense instructor will tell you that if you know a fight is coming and you can't avoid it, the best handgun to take to a fight is a long gun.