@tolik,
you are not wrong.
We are fighting a war from the Vietnam era where fire fights were in the jungle, at short distances. Comparable to urban hostile environments.
On paper, a 5.56 looks great.
Reality is a different thing.
While I was in Afghanistan, insurgents would attack from an elevated position, usually, but not always using an IED as the initial attack. Then, using PKMs (7.62x54R) and RPGs as the main effort to rain down rounds on the column usually from 500m (they knew the limitations of a 5.56 round at that range, up elevation and in Afghan winds, forget it. MG240s and M2 got the most effective use. M16/M4 were just wasting ammo). AKs closer in, in the supporting or harassment role.
And they had no body armor. They did small team hit and run tactics, beating feet on small motorcycles on goat paths. Meanwhile, our MRAPs could not go up that hill, or could overturn. A rolled MRAP is like a turtle on its back.
Bridges? Try taking a 13ton armored vehicle over a stone built bridge. All the insurgents had to do was get over the bridge. If a MRAP tired, it was going down into the ravine with a sudden stop at the bottom.
Wearing full body armor and kit and try to do a 100yrd dash, or run up a hill? Try it once. There is a reason why maneuver warfare is so important.
