65BR I posted something similar to your OP in another thread this week. I was talking more .257 calibre bullets though. Something in the 130-odd grain weight range, perhaps with BC numbers of 0.70+.
But I guess the 6mm crowd is chasing on those heels with the likes of the 110g SMK and some of those Bergers....
A risk with a fast twist .257 or .277 would be - I presume - that someone takes those long, VLD bullets and attempts to run them in a standard 1-10 twist and next thing they're taking their shiny new rifle back to the shop saying it can't shoot for crap!
