Dave, Richard Franklin is the one who came up with this combination of Cartridge, Bullet and Barrel twist to make this thing work. The 1-15 twist 30" Bartlien barrel is producing 4000fps velocity and excellent accuracy.
As I mentioned, I have talked to many guys who have a 300 Varminter and they are saying they are getting 4000+fps and accuracy in the .1's and .2's. The 300 Varminter is an awesome rifle for it's intended purpose.
The bullets you mentioned, allthough good, will not provide the same splat factor the 110 V-Max and 125grn BT will. The 1-17 twist barrels work better for the light bench rest bullets, but not for the 110 V-Max and 125grn BT.