.22’s HP’s are also a little messy to. They’ll cut up the guts if they hit a bone and splinter.
IIRC, the .556mm, the round used in the M16 is just about the same as the .22 caliber. Granted it has a lot more powder behind it and is longer, but it’s roughly the same diameter. BTW, it also is famous, when it hits a bone, for tumbling inside the body and causing extensive internal damage because of that.