Thanks for the response guys.

I had used JB for a couple of times but with little effect.
Then I asked around and discovered that I had not been using it hard enough. So following some advice I got I wraped a patch around a borebrush and passed it through the barrel 20 times and cleaned it with copper solvent.
Did that 4-5 times and finally got some results.

Best regards.

I used a JB treatment on a Sako 6.5X55 barrel and it took care
of the fouling problem but I was wandering if it can create an overbore effect. The label on JB can says that it cannot harm your riffle.

Best regards.

I think you'd have to scrub for several months to enlarge the bore.....

It'll wear out your arm way before it wears out your barrel..... HTH, Dutch.

Glad to hear you solved the fouling problem.

Did it help your accuracy?

Like the others said, you'd have a hard time wearing out the barrel w/ normal treatments of JB.

Good Luck!

Reloader

My experience with several barrels and a calibers is this: No, you will NOT wear out your barrel. Primary reason is that two of my barrels in particular that fouled badly, the cleaning and polishing action led to a point where neither foul enough to require it anymore. A dab of Sweet's or CR10 and I'm done. Still shoot as well if not better than originally. It is an abrasive, but the grit is so fine as to defy the definition. I'm not certain but suspect that the material used to lap barrels is coarser than JB.

Primary problem I've had with JB is that I never use a full container before it goes south in the container after about 7-8 years. I suppose I could troll the pawn shops looking for guns that need to be rehabilitated.

Dan, JB contains a grit about as abrasive as jeweler's rouge (about 1200). Barrels are hand lapped with grit in the 300-400 range. HTH, Dutch.

You would die of old age before JB enlarged a bore. However, you could cause serious damage trying to clean without using a good bore guide.

There are far easier ways to screw up a bore. Stainless steel brushes, for example. Or as said before, not using a bore guide.

I purchased a barrel from Hart barrels and it was a fouler, to say the least. I called an asked them about JB and they told me NOT to use it. Said it makes the bore too smooth, and that will cause fouling. I've never heard that before, or since. Guess the microfine finish in the best benchrest barrels are giving their owners fits.LOL

Jim

Next time you use JB, try it immediately after shooting, while the barrel is warm. It works much better like that. IIRC that's in the instructions also.

Dutch, thanks for that. Pretty fine stuff indeed.

That's an interesting comment about JB Bore Cleaner. I use it periodically in 11 different firearms and have never experienced any problems. I use it with a patch covered jag
usually in a firearm when the accuracy seems to have gone south. Occasionally I'll notice a diference, but not normally. I merely use it to prevent a crud build up. Best wishes.

Cal - Montreal

Cal, which comment?

Put a barrel in the lathe.
Spin it fast.
Rub on it hard with a cloth and JB.
Examine with a microscope.
Now rub hard for 10 minutes at full speed spin.
Look at the barrel again under the microscope.
See any change?
Now calulate how many times you would have to push the cleaning rod to make no change:
3600 rpm x 10 min = 36,000 revs = 72,000 inches = 2880 cleaning rod strokes.
At one stroke per 5 seconds = 4 hours of full speed cleaning.

I have been learning the ways to rifle accuracy for about 30 years and have learned some lessons the hard way. I read most everything in Precision Shooting magazine and every related source and most writers agree that JB bore paste will not harm your barrel.Some barrel makers however say "don't use it in my barrel"! Well, I had a new match grade stainless top brand barrel put on my pet 308 Win. this year. During the break in,neither Sweets nor CR10 was removing the copper very well.Don't know why it works sometimes and other times doesn't. I've never seen a discussion on that subject. I resorted to JB bore paste on a tight patch on a wrap style jag.A dozen passes usually got the copper out.Shot 3 more and JBed again until 50 shots of break in were complete.Fired 3shot groups for load development over the next days. Soon the copper fouling ceased.Of course I always rinsed with shooters Choice and finished with an oiled patch then dry patch before shooting again through a cooled barrel. This rifle fired a few promising groups at first then turned into a 1 1/2 MOA rifle.I tried EVERYTHING during troubleshooting. Finally I pushed a OO soft buckshot through the bore and measured it at .3088 groove diameter.WHAT? Well the gunsmith provided a chamber gauge made from a 2" section of the barrel blank. I measured the same way. It was .3078 groove diameter.SHOCKING! I mounted the barrel stub in the vise and used JB in it the same way I had during break in. With just 12 JB patches through that stub I "polished" that bore to .3083 diameter! Now I have used JB in my other rifles but sparingly. My 2 most accurate rifles (.35MOA and .5MOA) are still that accurate with many rounds through each. Each of these rifles has had maybe 6 JB patches through them. From now on I'll be using JB only to remove stubborn fouling as a last resort.

Hello DigitalDan,

I was commenting about whether it will cause an overbore condition. I read a couple of interesting threads on this at Benchrest Central a while back and the general opinion was that it would not. I use JB Bore Compound, but not religiously. Mainly if I feel my groups are opening in a particular rifle I'll give it a hard cleaning using JB among other things, but I don't make a vocation of it. It seems too much rigid cleaning can do almost as much to wear out a barrel and the shooting itself. I don't really know that for sure. What do you think? Best wishes.

Cal - Montreal

JAL,when I get the 308 back from the gunsmith with another new barrel,I'll use Sweets to get out as much copper as it will,and clean with Shooters Choice, and not sweat the copper that's left till I get home.Then I'll soak the bore with Hoppes 9 as you recommend.I got a bit obsessed about cleaning after getting a Hawkeye bore scope awhile back. Cleaning until patches come out clean had served me well in the past and I didn't ruin any barrels that way.Thanks for your advise. It's one method I'd heard of but never tried. Thought it was for softening cooked powder fouling.

I must have a wimpy jar of JB.

I can't get any meausured change, even with soft 22 rimfire barrels.

I'm with you, Clark. I routinely run about 500 passes with J-B through new barrels in order to polish them and I've never noted any change when slugging before and after.