Shooting & hunting with the 270 Winchester since '66 and beginning in 2012 shooting an edge and then two forms of Ackley improved 338s... The present is 1:9.5-1:8 twist and sends 256 gn Flatlines out the spout at 3410 I've become rather partial to gain twist and monoliths. Just prior to discovering this thread I remarked to a friend--and participant here also--that If I was to replace my 270 barrel It would be either a 26" lt. varmint 1:9.5 or 1:9 - 1:7.5. I shoot only copper; Barnes since the '60s and others including the already mentioned Flatlines, Badlands Super Dozers, Cutting Edge, etc. Aside from actual hands on experience all that was preceeded by research. The latter continues obviously.you’ve done this? what can you share?