i would go either 8 or 7 1/2 twist ,Berger bullets is coming out with some 135 gr. bullets soon so the rest of the bullet companies will too. i built a 257 Creedmoor shoots 115 gr and bigger up to 131 gr. bullets great also i have 2 - 257 Roberts i had rebarreled with 7 1/2 twist and both shoot 115 gr. bullets super. since Creedmoor brass is easy to find you might wanna consider a 257 Creedmoor too ? just a thought,take care,Pete53
