Alternative to 6.5 Grendel?

[Trooper]

The problem with holding down COL to a minimum is that you are liable to end up without enough space to load long-ogive bullets. This problem affects the 5.56x45, 7.62x51 and even the .338 Lapua Magnum (which is why the .338 Norma Magnum was developed). This won't matter in short-range weapons but it surely does if you want a decent long-range performance.

Thus a 6.5x45 would do well as a replacement for both the 5.56x45 and 7.62x51. And then use the 8.59x64 (.338NM) in the med MG to replace the .50 cal M2.

Most of the troops would not need a long range weapon (20 inch barrel for the DM) and would only use 16" carbine. But a 6.5x45 would give the penetration at close quarters that the 5.56x45 does not have. The 5.56NATO is just too light to go against brick or stone buildings. Russians found that out with the 5.45x39 in Chechnya.