Apparently testing on body armor out to 600 meters,showed the sweet spot was with a 277 inch 140 grain projectile at 3100 fps at the muzzle.
Next they wanted it in a suppressed platform with a reasonable overall length,in a 16 inch barrel in a case about the size of a 308 it took 80,000 psi to get there. Hence the need for the hybrid case of brass with a steel base.
It is a lot of effort and expense for something that may not work in the real world.
They could have gone with a 6mm ARC and had a much more powerful cartridge than the 5.56 in a more reasonably sized platform. With the correct 110 grain ammo,it would do most anything you needed.
The squad automatic weapon could have been for the larger cartridge as well a long range rifle for designated marksmen.
Trying to do everything with the larger cartridge kind of created a Frankenrifle. A big bulky rifle with bulky ammo that will be an undue burden on regular soilders, and probably lead to failures in the field because of the high operating pressures and the tight tolerances required to contain it.
Last edited by ruraldoc; 02/07/24.
