I am about to order two Shilen Select Match Barrels for builds that I have upcoming. The first is a .338 to build a .338 Ultra Mag on and I am thinking of a 1 in 8 twist. The other is a .308 to build a .300 Ultra Mag on and I am considering a 1 in 10 Twist. I would like to shoot up to 300 grainers out of the .338 and up to 220's out of the .300. Am I on the right track with my thinking about the right twist here? I would appreciate any input you may be able to offer. I have a little cash laying around right now and thought I would start assembling some parts for future builds. Going to pick up these two barrels and two 700 Actions for some sporter weight rifles to take to Alaska and Africa in the next couple of years. Thanks for your help.