The military is talking about replacing the M9 again, which always stirs up a caliber war about whether or not 9mm is a suitable manstopper and why the military doesn’t like it. But remember: the military can only use FMJ ammo, no hollow points.
A small, fast bullet is more likely to overpenetrate than a fat, slow bullet in FMJ. When they’re both hollow points and both expand and discharge all of their energy in the target, the difference is much less significant.
So don’t throw away your 9mm CCW guns, just make sure not to load them with hardball for carry.