I am not certain on the breechface diameter, but I believe that it is different. I know that the 7mm is a lot longer rd than the 308, so you will probably need a different action. makers sometimes try to make one size fit all, tho, so it's possible that you can get by with the same one. Sounds like a big waste, tho. Why not just get an action, if you are going to scrap all the other parts? Check out the gunsmith mecca, Brownell's supply, google for it. Their smiths are a huge help, usually.