Ken,
9" has been the US standard for the 6.5, and I used a 9" Shilen barrel on my 6.5-'06. I can shoot up to 160 gr RN, but not 165 gr semi-spitzer (it is the length of the bullet that matters).
The Euro standard is 7.87" (i.e. 200 mm), and you need that twist to shoot the really long and heavy 6.5mm bullets.
jim
