I understand 8 inch twist is all you need for the 6mm heavy bullet.
I would use what Berger recommend. why not a 243 Win as it is proving extremely accurate with the 115 DTAC for long range shooting up to 1200 yds. (ref. US sniper match winners). It has low recoil and you get 3150 fps with RE 25 powder in a 26 inch tube.
I understand 8 inch twist is all you need for the 6mm heavy bullet.
Re: the 243 It has low recoil and you get 3150 fps with RE 25 powder in a 26 inch tube.