The Army damn sure needs to up the calibre of any future rifle.The 5.56 is just to weak against drugged up thugs.
They should have learned that in Iraq fighting the drugged up terror creeps.
The Army insisted on only 5.56 mm for testing purposes. Multiple calibers are an option after selection.
The problem with the 5.56 in the M4 is that short barrel along with a heavy bullet just doesn’t get enough velocity to be effective.
I think with a 20 inch barrel it has been fine. If you have to go slower, then a larger caliber should do better.
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.