18" barrel. Plan on shooting mostly 120 range bullets out of it, which would point to the slower twist. I would like it to be able to run 140's if that's all I have at the time. I am running an 8 twist .260 right now and it works great for the 130 to 140 grain slugs but this barrel is done training and time for a new stick. Has anyone had any experience with the 107/120/123 bullets out of an 8 twist? What about 140's out of a 8.5 twist?