If I got pelted by a metal object the size of a baseball in real life that would hurt... So therefore I recommend making them do 2-3 damage if they hit you and 5 if they hit you in the face!
i don't really see the point and i don't really see it affecting gameplay that much unless damage was higher so eh
Seems extremely pointless for just frags and it can't be all nades (which would make more sense since they are also metal) because of inherently harmless nades like smokes and discombobs