I just finished reading the book Black Hawk Down (I know - I’m about a decade late on that). I was amazed to read about how much our troops hated the 5.56 ammo. There were several instances in that battle where they had to shoot someone 10-15 times to kill them.
Yeah, it’s small mass and high velocity gives it crappy stopping power at close range. It’s the same problem with the 9mm. That’s why SOCOM uses the Mk 23 .45ACP pistol instead of the M9 9mm
Also didn’t help that the locals were high on khat.