Re: WOW!! 338/408 Atacker.
The guys ive talked with that have a std 338 chey-tac reamer are getting 3150 on average. I dont know what bbl length they are using or powder charges. I suspect 3200 would be a good idea. figure out what bullet your going to use and pick the twist for it. The 300MK likes the 11" twist, 9.4"... 10" work good also. Mine will shoot bug holes with the 11.25" twist, but will not stabilize anything over 300 grns. If you going to shoot bigger then drop the twist to at least 10"
I have lots of info on this wildcat.