... It appears after a recent Parkerizing & Moly-Coat finish to a new gun the bore is full of gritty crud my Break-Free soaked swabs just haven't cleaned up. It even appears as dirty as when scrubbing commenced.

... Does it just require persistence and patience swabbing until smooth and clean?

... Ideas?

My brother had a LW barrel park'd and he freaked when having seen the bore.  He called Walther and they said "clean it and shoot it".  Best sub-MOA '93 7mm Mauser I have ever seen.

Dave S

Bore-Tech rod, Pro-Shot jag, brush and patches, Hoppes#9, JB Bore Paste.

We soaked a patch (get one out of your stash or cut to fit and that wraps around the brush with @ 1/16" overlap) with #9 and pushed through the bore.  About 4-6 patches ought to do it.

Then we did the same thing but added JB Bore Paste to the patch for about a dozen passes.

Flushed the chamber and bore with Gun Scrubber, dry patched, and fired Georgia Arms 7mm Mauser 140gr Nosler Ballistic Tip (Precision Plus).

Sweet.  

Sounds like the bore wasn't plugged before they Parkerized it, and the phosphate coating took on the inside of the bore. Not dangerous, might or might not affect accuracy for awhile, but really piss poor behavior.

Using a bore cleaner with a mild abrasive will get enough of the crud out to make the bore look better. Shooting a few hundred rounds thru it will take more out, but you'll probably never get all of the residue out of there.  Again, if it doesn't affect accuracy--no big deal.  But how will you ever know for sure?

Had a 1917 Enfield once that had been arsenal reparkerized with an unplugged bore.  It shot OK, but I always wondered if it would have done better if they had done the job right.

Hey, thanks. So it sounds like it's not unusual.
Now, it's a 50BMG and damned if Bore Snake does not make a 1/2 diameter snake. They have .410 and .550 (28 gauge). I cannot even find a rod the length needed.
For now I've threaded two (2) foot 3/8" diameter aluminum rods together for the job and just fashioned a makeshift jag for the swab.

... You Big Fifty guys, are there any spots out there for your "special" needs?

... I kinda feel like a lefty!