Hey Jim,
I have been campaigning what I believe to be an Obermeyer for the past two seasons with a 1-17Shilen on it shootin 118-7's ahead of 45.5g of N-140. The rifle has done very well often for me. It has an Aluminum butplate on it so I haven't looked for max juice but have found pressuer above where I am shooting it.
I see no advantage to the 308 over a say,30-44. I plan to make this my last 308 for the forseeable future. I see absolutely no reason to shoot an overbore case with light bullets. I see no reason yet to shoot heavier bullets that 118's. P.