Picked up a brand new Sako A7 a couple of weeks ago, its a medium weight fluted stainless barrel, threaded at the factory. Was just wiping it down last night when I noticed what looked like a faint dark ring on the outside about 5mm down from the threaded end, its not perfectly round - kind of wavers, tried to wipe it away with carbon solvent but it wont budge. Just wondering what it is (my moderator uses a delrin bushing that doesn't actually contact the barrel, and if it did the contact point is about 4" away). Possibly a tooling mark from some sort of steady used when cutting the muzzle threads?
Anyone else seen this on Sako (or Tikka) stainless barrels?