Re: 7mm-08 Gas Gun
Very good barrel life, much improved ballistics over .308. I am thinking the of an AR in 7-08 as well. When Seekins comes out with their AR-10 lower receiver, I expect to buy one for a 7-08.
7-08 is an excellent compromise, but for comps you would be better off with 6.5 or 6mm Creedmoor.