Does J.B. bore paste .....?

[forquidder]

I'm cleaning out a new stainless barrel prior to break-in.
I used Kleen Bore #10 copper cutter until the patches came out clean. I thought I'd touch up the last bit of fouling with some J. B. Bore paste. 10+ patches later they are coming out dirtier than ever.
Does this stuff work similarly to other metal polishes in that what I am seeing is the result of the metal polishing off and if so, how would one tell when the barrel is clean when using it?
I realize they put a few rounds downrange to test out new barrels but this is ridiculous.

 

[Ol` Joe]

I find the abrasives tend to keep comeing out black as you are seeing. Try rubbing a J-B soaked patch on a piece of steel and it will blacken even though the metal is clean.
I quit cleaning when I can`t see fouling in the bore with a good light and Q-tip. The Q-tip pushed a couple inches in the bore will usually reflect enough light to see by.

 

[Oldtimer]

I've never used J.B.'s bore "paste", but it's probably similar to their bore "polish". It is MILDLY abrasive, but it works great for polishing the bore. The abrasive action isn't harmful to the bore, but it DOES smoothe-out the machine marks in the grooves and on the lands of the bore.

You can continue to use J.B.'s "paste", as far as I know, without having to worry about the patches coming out dark. Just use it sparingly, and run some oiled patches/dry patches through until they come out clean.

J.B.'s bore "polish" is one of the first things that I use on a new firearm, besides shooting the "break-in" rounds and cleaning procedures. The "break-in" rounds tend to cause the striation of the steel to be directed toward the muzzle, which is what you want. Cleaning the bore with a BRONZE brush/solvent removes the copper/lead fouling, and the bore "polish" works to smoothe-out the correctly-directed striation marks within the bore.

Just be sure to oily patch/dry patch the bore, to get ALL of the "paste" or "polish" materials out before shooting!