Would a 6.8 be about the same as the .270? I have long thought that if we up-sized our ammo that the .270 would be about as powerful as the .308, and a little flatter shooting and lighter than the .308 [7.62]. Unless I'm mistaken, isn't the .270 a short action cartridge like the .308?
So much for my rifle cartridge knowledge. It's the .270 Wincester Short Magnum that is a short action round. Maybe it could be modified to work in U.S. military assault rifles. If not there are the two excellent short action rounds, the .308 and the .243.
I would think... I flagged some folks in who do know...