This thread is 12 years old, but same holds true. Lighter the bullet, the slower the twist(1:10), if you were to run a heavy bullet, the faster the twist(1:8/1:9) If you're dead set on the 6x45, i'd look at the 65gr vmax, 70 BT from Nosler(which is unobtanium) and i'd run a 1:9 twist, which...