There is nothing wrong with the 5.56mm cartridge. The problem is the bullet. It’s designed to go through light armor and it does that well. What it sucks at is expanding rapidly and dumping its energy into the target. A 62 soft point is absolutely devastating at all but the most extreme ranges.
Even an open tip projectile would be a huge improvement.
Even an open tip projectile would be a huge improvement.
The Geneva Convention would not allow the use of open tip or hollow point bullets in warfare.
Hardball only.
I think the Swedes had it close to figured out long ago with the 6.5mm x 55 Swedish Mauser.