308sako,
I'm curious also. I'm guessing that you will be right on the edge. Since you're there and have the rifle, give it a try and let us know what you find out. 8 twist with a 6/250 Imp at 1400 didn't work well for me with 115 Tubbs. I expected Bergers being longer to be more problematic yet in my setup and didn't try.
Greg