so im looking at a few del-ton uppers , the 20 inch . Thay are only 1 in 9 twist and some of them up can get crome lined barrels. ... so , are the crome lined barrels any less accurate than a standard barrel? Also this will be a target gun with iron sights and what i gather that a F marked front sight is long range . I can get it with a standard A2 sight . It will only be used out to 300 yards. Im thinking a 1 in 9 will only handle a 69 grain bullet and no more. Any info helpfully. .