01-17-2014, 09:57 PM
One thing. With comparison to the .308, the 6.5x55 Swede is the standard. Thus the .260 Rem or the 6.5mm Creedmoor come close. The 6.5x47 Laupa comes up a bit short. The standard is to move a 6.5mm round weighting 140 gn. at 2550 fps out of the barrel. That would be equivalent to the .308 with a 192 gn. bullet. http://www.eabco.com/6.5_mm_cartridges.html
Thus it would be difficult to make a round that would fit into a standard M4 magazine well that would be able to compare to the 6.5x55. Especially using a 140 gn. bullet. Thus we would be using a smaller round but might be able to do about 80% of what the .308 does. With a lot less recoil.
If we need a heavier round for a medium MG, the .338 NM (8.6x63) would do. the .338 has a similar BC (.600) to what the 6.5mm has.
Thus it would be difficult to make a round that would fit into a standard M4 magazine well that would be able to compare to the 6.5x55. Especially using a 140 gn. bullet. Thus we would be using a smaller round but might be able to do about 80% of what the .308 does. With a lot less recoil.
If we need a heavier round for a medium MG, the .338 NM (8.6x63) would do. the .338 has a similar BC (.600) to what the 6.5mm has.