HB,

Had a similar dilemma myself not too long ago. I'm building a 260 rem using a Criterion Varmint Barrel. I asked the same question, Varmint or Bull. Some of the other guys on here told me this: take a pair of calipers and open them up about .17. That is about the difference in contour between the Criterion Bull and their Varmint... (at the muzzle) There's barely a hair's width difference, But the bull is about 1.5 lbs heavier. The Varmint will be sufficient for anything you'll probably want to do.