I have a 32" RUM bbl on order, and my choices were 8, 9, and 10. Since I am currently the shooter of relatively light bullets (140 Super Shock Tip), I didn't go with the 8 twist. But with this heavyweight making so many waves, claiming to be the "king of the mountain", in terms of slipperyness, I'm having a hard time ignoring it. Especially being that it IS in MY caliber. Any ideas on how tight the groups would be at say 600yd, compared to the 140 SSTs? I'm very generous with the amount of powder that goes into the cases.