Re: accurizing a remington
Before even considering using a factory barrel you want to inspect the chamber/throat for extreme run out issues and you want to slug the barrel to feel how consistent the bore diameter is.
Having a consistent bore diameter is more important to accuracy than having a concentric chamber, so some barrels will either need to be lapped or just replaced.
We have set back barrels that were unable to remove the chamber/throat run out, but the barrel was extremely smooth from chamber to crown and it shot as good as a custom barrel.
If you want to remove the run out, you need to cut off about .700" of the existing barrel (heavy contours only) then bore out the chamber so its concentric. Dont bother using a PTG rod to indicate the chamber in because it will give you a false reading of the bore. Then your reamer will start in the chamber straight, and cut concentric.
Honestly, its so much work just to use a factory barrel again, just put on a good quality barrel and be done with it.
Mark