The lighter the bullet the slower the twist rate. For a 52 gr. bullet a 1 in 12 twist or 1 in 14 twist is best right up to 60 gr. The heavier the bullet the fast twist is needed like a 1 in 7 for 62 gr. and up. A 1 in 9 twist is an all around rate that will work with most bullet weights but favors a heavier bullet a bit better.