Home Forums Hunting & Shooting Ask The Gunwriters Bore Scope, JB's Bore compound and VFG pellets........

Yeah, since when is aluminum oxide not abrasive. In using the stuff it always seemed very, very mildly abrasive with a very fine grit that polishes clear plastics well. More often I'll grab Simichrome for its little bit stronger abrasive quality. Both good polishes.

I think the only abrasive in JB is bone meal. I don't think that would be agressive enough to harm steel.

Varmint Al says you can polish a steel cylinder 'till the cows come home with Flitz and it will not reduce the O.D. enough for you to be able to measure it with a micrometer.

Al was in the Mechanical Engineering department ( as I) who did structural analyisis while at Livermore, but retired before I got to know him well but I have co-workers who knew Al.

Not to discount his views, knowledge or writings, his great graphs and shooting skill and such... The article you refer to was the outside of a rod turned in a lathe.......


JB is a lapping compound, as is Flitz ( albeit I don't know what it is, but I have read it is more agressive than JB for polishing metal) and Al's point is correct on polishing the outside of a bar of steel... the polishing of the inside of a barrel has little to do with what Al wrote..... Or BARREL MAKERS wouldn't lap a new barrel to make it shoot better.....


Just saying your referencing Al's findings was totally opposite it's application in HAND LAPPING a barrel's bore.

Allen

Dang internet...

Looking at the MSDS Flitz ia alumina oxide and ammonia.......

Which does work.

From what I remember (which may be faulty) JB Compound is essentially a low density mixture of jeweler's rouge (iron oxide).

Hi John. The 'cutting' agent in JB is diatomateous earth...which is primarily silica with small amounts of iron oxide and alumina.

JB is good stuff.

Good shootin'. -Al

Here is the text from Al's website:



POLISH THE DIES.... I polish the inside of my rifle reloading dies. Most die manufacturers leave the die bores smooth but not polished. A polished die will resize with much less axial force than one in the as-received condition. I disassemble them and put a little Flitz on a cotton bore mop held in a drill motor and polish each one for 30 seconds or more at a 300 to 600 rpm speed. Sometimes I have to wrap a paper towel around the swab to get a good fit. Then I clean all the polish out with hot water and dry with a paper towel wrapped around a clean cotton swab. The polishing process does not remove a measurable amount of material, but results in smoother operation, minimizes the scratching or scoring of the brass, and minimizes crumpling problems when I use them while forming wildcat brass.



Flitz is slightly more aggressive than JB. I took a piece of mild steel with a reasonably smooth finish and polished it with Flitz and JB. The left end was polished for about 2 minutes at 500 rpm with Flitz and the right end for about 2 minutes with JB. There is no detectable decrease in the diameter on either end measured with my high-precision Mitutoyo Micrometer. It was a very easy test. Try it for yourself.

My opinion is that you can not hurt a barrel will Flitz, JB or any of the other polishing compounds and if mixed with MPro 7 are the most effective powder removers I have tested.

The lapping compounds we use to lap the barrel are a whole different animal.

Thanks Mr Burns.

What material (Si-o, Al-o ?) and grit do you use to polish a barrel?


Allen

The subject of the abrasive in J-B pops up every couple of years on the fire. The abrasive is aluminum oxide, and the base is a soap-oil mix.

The original J-B was developed by US Products: http://www.us-products.com/home.html. They are a manufacturer of abrasives, principally aluminum oxide. (The website is not well organized, but there's a lot of information there.)

For a while, US Products made a liquid abrasive bore cleaner marketed as "Gold Medallion". I had a bottle of it in the early 90s. The product was good enough that Remington bought it to sell as "Rem Clean", and Gold Medallion disappeared.

J-B stopped being sold for a while, and US Products brought it out again as USP Bore Paste, which is now sold at least by Midway (Product #257358). Brownells obtained the J-B name and sells their version.

Poster bobski wrote that J-B has a grit size of about 2500, which would make the abrasive particles about 5 microns in diameter. I looked at some under a microscope once, and the little clear particles were about that size.

--Bob

Hello DJ,
When looking thru your bore scope what part of the barrel are you seeing the most jacketed fouling?
Throat?
Muzzle?
Uniform through out?

Thanks

I assume you are asking about the lapping compound for barrel lapping?

We use the standard Clover oil based silicon carbide.

Thanks John

Do you make a lead slug, and what grits do you use? I wouldn't do it myself, just curious how much more agressive a gunsmith would do vs me using JB to remove copper.


Thank you

Allen

I had a SS match grade barrel fitted to a Ruger Ranch rifle and the smith's break in instructions included a Bore Snake wrapped wth some 4-0 steel wool and coated with JB. After each shot, three pulls followed by a clean Bore Snake. That really worked well. Occasionally had to use some copper solvent, but not that often. The barrel cleans up fast and doesn't foul that bad. And I do have a Hawkeye to check it out.

JB has been around so long and is such a proven product that I will stay with it. The JB/Kroil combo has seen some attention.

I think the brush's main damage is at the crown as it is repeatedly pulled back through the barrel. A bore so treated over time can show evidence of damage at the crown, as seen thru the Hawkeye. I seldon use a brush, don't really see the need. I've read that technically, the brush should be unscrewed from the rod when it clears the muzzle and reattached for another push. That's too much trouble and takes too long for my taste. My favorite cleaner is Butch's Bore Bright.

DF

It is where it is in each barrel and is different in each barrel so far.........................DJ