Another consideration may be energy and intended game. You said hunting, so if your mainly after deer, then I would go 6.5, however if you plan on hunting elk with it, the 7mm would be my choice. Not that the 6.5 won't do it, I kill elk with a .260ai, but the 7mm will just do it better. 180 will have a good bit more energy at a given range than a 140, not to mention larger bullet diameters tend to kill better, even with the same energy.
One more thing to think about, possibly look at the 6.5mm and 7mm sherman shortmags, if you don't mind fireforming they will net you a decent amount of performance over the SAUM, and headstamped brass is now available by ADG. Also, you will have a shorter OAL with a given bullet in the SS, and likely be able to feed in a short action.