Home Forums Hunting & Shooting Ask The Gunwriters JB bore Compound?

This^^^^^^^^💯

There are two versions of JB. One of them looks like aluminum oxide and the other looks like jeweler's rouge.

Two different types of sand. MSDS contents Almadine Pyrope Garnet.

Almadine garnet sand is deep red to pinkish in color and is the most abrasive of the two

Pyrope garnet sand is red to black in color and softer than Almadine.

Basically you are cleaning your bore with vasilene and sand.

After reading David Petzal singing it's praises, I bought my first jar of J-B compound.
Someone please explain your cleaning procedure using it. Do you use it every time you clean your barrel? Not new to rifles and cleaning them, just new to this product.
Thanks.

Can't speak for everybody but I only use it for heavily metal fouled barrels.

Had a .243AI so fouled in front of the chamber you could feel the constriction with a tight patch. Soaking in copper solvent got a good bit out but 30 strokes with JB on a patch around a brush got it all out.

Just cleaned up a new2me .30-30 bolt action with who knows how many years of fouling in the bore. It is to be used for cast bullet shooting so I wanted to get out all metal fouling. Copper solvent got out 90% of it but about 15-20 strokes of JB got the rest so I'm starting off with a perfectly clean barrel.

Fwiw, situations like this are where a borescope earns its keep.

Bought my one and only jar maybe 20 years ago and it's still half full. Finally bought another jar last month since the old one was getting pretty solidified - probably could have rejuvenated it but I splurged 'cause I'm worth it.

My last major use was part of a "recovery operation" on a very neglected barrel. (Not my neglect by the way.)

Thanks. If 600 grit compound is the finest stuff the pros use to lap, it is a good marker for this type product.

The main thing about JB is that it is softer than steel and like pumice or rotten stone it breaks down to a finer grit in use. I made my own with Vaseline and Diatomaceous earth that was food grade. It was very aggressive and I think hard enough to embed in the barrel so I quit using it except as a polish for exterior applications. I heard of one manufacturer using it in tooth paste until they found out it would wear tooth enamel down quickly, not good.

Diamond grit might have even a greater possibility of embedding in the bore and it will not break down into a finer grit with use.

Forgot which barrel maker it was, possibly Hart, they only go to 220 grit in lapping their barrels.

I thin the JB with Kroil with the theory that it would lubricate the abrasive action and might help get under any fouling and speed the operation.

Wow. Thanks for all the replies. I got busy and didn't get a chance to look at this for a day. I have a 22-250 that copper fouls and loses accuracy quickly. Also a 222 that has a little pitting in the bore. That motivated me to get a bottle of Dyna-tek, but in trying to get down to bare metal before applying it, I ran into the JB issue. Hopefully I will be able to get back to it and try some things in the next couple days.

Jerry

DBC is good stuff, but you gotta get it down to raw steel for optimal application.

I like the idea of Kroil to rehydrate JB's, have an old can with hard stuff that needs that treatment.

DF

On a pitted or really stubborn bore I take the easy way out and shoot some of the Tubb's final finish rounds. This can help if the throat is going and it will take a lot of copper with it. This on questionable barrels only not the customs. You will still need to go through the cleaning drill but it will be mostly the pits and bottom of the grooves that still have copper after the final finish. I feel fine if the throat is moved slightly and the wear on the barrel is comparable to a 100 rounds or so. If not successful then I am that much closer to getting a new barrel so no pain there.

Keith,

I tried Montana Xtreme copper cream and it didn't seem to clean as well as JB compound according to my bore scope.

I wonder what the difference is between the regular Flitz polishing compound I use on my dies and Flitz bore polish?

I cut it with original Hoppes No. 9 to create a fairly thin slurry. Has worked well for many years.
Still using a jar I bought in 1968.

In the mode of confessing our sins… I will admit to using fine valve grinding compound on a bad bore one time over 40 years ago. It worked. The rifle improved accuracy dramatically.

I shot some military surplus ammo one day in my 03-A3, and did not get it cleaned that night. I think it was the very next day that I was horrified to see a fur like growth of corrosion in the barrel. Cleaning it removed the fur but not the heavy, erratic lines of etched metal.

I was somewhat isolated that winter in Canadian hinterlands. So I used the only thing I had, which was valve grinding compound, and I used the fine side of the circular double sided container. I can’t recall now but think that I made five precisely identical passes each direction through the bore with an evenly coated tight cotton patch, then scrubbed and cleaned out all trace of the abrasive. A fine etching remained visible in the bore. I assumed that I had ruined the barrel.

While I was at it I took a brass round head Phillips screw, coated it with some of the fine grind valve compound and carefully and slowly rotated it by hand in the muzzle, cutting/polishing the end of the lands and grooves. I tried to be consistent and equal with angles and rotations each direction.

I'm not sure why but that rifle suddenly started shooting consistent half inch groups with 165 grain Sierra bullets. Before the corrosion and treatment it had consistently shot about 1 MOA with my best handloads. The barrel never quit showing the fine etching.

After 20 years as my only big game rifle I traded it off to buy a new Remington 700, and have never found as accurate an 06 since, in a half dozen tries. Wish I had it back, etched bore notwithstanding

Turns out the Kroil worked pretty good for a thinner on the JB. I put some of the JB in a small container and added a good squirt of Kroil. A little mixing and it was back to a light paste. With some thorough scrubbing and then a few patches with #9, the bores looked really clean. I applied the DBC yesterday and made it to the range to do the 10 round cure today. Interestingly, the first shot out of each rifle went significantly high, the second shot was only a couple inches high and then the rest settled in to the normal place. That was about all I had time for.

When I got home, I took a look with the borescope. I will have to do some more shooting to see if it gets any worse, but first impressions are not great. I am pretty sure I can see some copper streaking on the tops of the lands and some little black specs that I am not sure about. Wish I could take pictures through the scope to get some feedback.

Jerry

The curing shots often result in a lot of fouling. Clean the barrel after the 10 curing shots, and every cleaning cycle will result in less following.

+1

DF

Does anyone on here believe like Will Shumann does and only put bullets down a barrel. He wrote a famous article on not cleaning. wish I had a link.

Not me.

But, a lot would depend on the round and the barrel. I can see that with .22LR and such.

DF