A 1-12 twist will handle most bullets up to about 190gr. A 1-10 twist won't give you any better accuracy. Most of my barrels on my guns are 1-11 or 1-11.25 and I shoot primarily 155's and 175gr. bullets. The only reason to go to a faster twist like 1-10 is if you intend on trying to shoot bullets heavier than 190gr.
Later, Frank
Bartlein Barrels
