6 Arc, one of the Grendels, .300 Ham'r, 6x45, 6.5 Arc, .223.......
Pick your poison.
I'm just getting set to build another UL-UL straight pull AR in .300 ham'r for a friend, specifically for your exact needs. I lent him mine for a couple of hunts & according to him, it 'better mousetraps' all...