I don't claim to be an expert by any means, but I find Gale McMillan's (who could be considered an expert) thoughts on the subject interesting at least. See http://www.6mmbr.com/GailMcMbreakin.htmlnothing said:What does the break-in process actually do to the barrel? I can't imagine what shooting/cleaning cycle with a 100 rounds of lead or copper/nickel though a hardened steel barrel would really accomplish. Especially if it was a match grade barrel.
That is interesting. I know JB has been used by many folks for years, but in the link at the bottom of the page I linked above there are additional comments by Mr. McMillan on the subject, and he said that when someone uses JB on one of his rifles he voids the warranty.Doug Bowser said:For breaking in a new barrel, I fire 3 shots, clean with Hoppe's #9 and dry the bore. Stroke the barrel 10 times with a tight fitting flannel patch with JB Bore cleaner on it. Repeat the process at least 6 times.
This is the procedure I learned at Camp perry and the same procedure used by Bushmaster when breaking in a match AR15 barrel. On the Wilson Match barrels used on Rock River Ar15 NM rifles, the barrels are fire lapped and require no break in period.