Re: Barrel Bore Defect?
I spoke to Krieger. According to them...,
The marks (scratches) are the result of using a crowning tool. Normally, the marks are minor and if they pass inspection, the barrel is shipped to the customer. The marks on barrels that pass inspection are very light, smoothing out and disappearing with barrel break in. The marks were not lapped out as excessive lapping can degrade accuracy and damage the crisp crown. The marks generally do not present a performance problem. It was noted that such marks are highly reflective and may look worse than they are.
They said a crowning tool is used to provide a uniform crown, and that it is a little easier and faster to accomplish that with the crowning tool.
The stated using a boring bar many times would require an additional set-up to assure that the crown is uniform 360 degrees around the bore and that the pilot on the crowning tool takes care of this a little quicker.
Was told the volume of barrels produced sometimes requires use of production type methods that still preserves their quality standards.
I am no machinist, and don't know how these tools and the process work, but this is what Krieger told me. Perhaps someone more knowledgeable than I could comment.
It was felt that after learning of the parts in my rifle, and with use of this barrel and quality ammo, the gun should be capable of .5 MOA or better (if I can do my part).
I was asked to shoot the gun and report back on performance, assuring me they stand behind their product and want to be sure I am satisfied.
Will advise on performance.
- Phil
