Bore-Scope Pictures: What are these lines across rifling?

ddjchemist · Feb 21, 2022

I recently got a bore-scope and scoped all my rifles. Here I posted a picture of near-throat area of my Tikka Tac A1 w/ about 1,500 rounds through. The barrel is shot-out and I am taking the rifle for barrel replacement next week. My gunsmith will install Krieger Heavy Palma 24" 4-Groove barrel. The Tikka factory barrel was very accurate until about 1,100-1,200 rounds and then within about 200 rounds went from sub-1/2 MOA to over 1.5-MOA. I checked the barrel with a bore-scope and the area near throat is badly fire-cracked, but throughout first 1/2 of the barrel I see some thin lines about 45 degrees to rifling. You can see them in the posted picture. Does anyone have idea what these lines could be? Could these be cleaning scratches, or could these be marks left by the factory?

Dan from Seattle

Steel Head · Feb 28, 2022

Could be a defect in the mandrel when it was hammer forged or an artifact of the process.

Bit surprised it died so fast unless it's a magnum of some sort.

P7M13 · Feb 28, 2022

Sako proprietary "accurizer" marks.

ddjchemist · Feb 28, 2022

I shot the rifle too hard and that is the reason the rifle is going to re-barreling tomorrow. I was shooting 25-30 consecutive rounds without barrel cooling. Pretty much I fried the barrel.