Is Over-polishing a barrel a thing?

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Certainly not me. That was my point. I was "trying" to over polish a barrel that I was going to throw out, using JB products only, and it didn't happen. I agree that you can over polish by hand with minimal effort using the wrong product but I have yet to hear or see someone who actually did this with JB. That is why I recommended the op stick with just using JB and it won't be a problem.
 
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Certainly not me. That was my point. I was "trying" to over polish a barrel that I was going to throw out, using JB products only, and it didn't happen. I agree that you can over polish by hand with minimal effort using the wrong product but I have yet to hear or see someone who actually did this with JB. That is why I recommended the op stick with just using JB and it won't be a problem.
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Yep. If bore damage was possible with anything short of grossly incompetent use, JB would have been out of business long ago. The term "lapping" is often and seriously misused when it comes to bore treatment. Lapping is done with a lead lap formed from the bore, and then used with lapping compounds of varying degrees of grit. Some custom gunsmiths use the process to form a choke at the muzzle. And of course it can also be used to repair bores with minor machining damage. Fire lapping is sometimes done in CF rifle by coating the bullet with compound and simply shooting it. Obviously, lapping is something to be done only by someone very knowledgeable with the process. The polishing discussed here is a cleaning process. As far as I know, the only metal it is likely to remove is small burrs left from the rifling process, and I expect it is those instances that receive the comments on the impressive results obtained. 
 
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Certainly not me. That was my point. I was "trying" to over polish a barrel that I was going to throw out, using JB products only, and it didn't happen. I agree that you can over polish by hand with minimal effort using the wrong product but I have yet to hear or see someone who actually did this with JB. That is why I recommended the op stick with just using JB and it won't be a problem.
Click to expand...

Yep. If bore damage was possible with anything short of grossly incompetent use, JB would have been out of business long ago. The term "lapping" is often and seriously misused when it comes to bore treatment. Lapping is done with a lead lap formed from the bore, and then used with lapping compounds of varying degrees of grit. Some custom gunsmiths use the process to form a choke at the muzzle. And of course it can also be used to repair bores with minor machining damage. Fire lapping is sometimes done in CF rifle by coating the bullet with compound and simply shooting it. Obviously, lapping is something to be done only by someone very knowledgeable with the process. The polishing discussed here is a cleaning process. As far as I know, the only metal it is likely to remove is small burrs left from the rifling process, and I expect it is those instances that receive the comments on the impressive results obtained.
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elh0102, I think your conclusions and observations are spot on.


Here's another JB story: I bought a pb bolt gun and in running the bolt I could hear the machining marks catching somewhwere. It sounded like a high pitch zipper zing. Now, everyone always talks about old bolt guns and how they get smooth over time, which is true and got me thinking about it. How many times did hunters shoot there rifles? Seriously. In days of old, who had the time or the money, or the horse, that could carry that much ammo to seriously break in a bolt gun? Not many, which is why it would take so long. Few, and I'm guessing here, would just sit around working the bolt either. I believe most of the old smooth guns came from the factory with a level of finish that is just lost these days. So, I decided to do a second experiment with JB and I slathered my bolt with it and ran my action (I $h!t you not) 5000 times. It did get a little bit smoother but there is sometimes just a little bit of the zing left. JB does a great job at being more abrasive than lead and getting at it, but it is not wearing down steel. I attribute whatever smoothness I got to simple wear of the steel on steel.
 
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OK, so which one of these is the best to use when cleaning a barrel? Will the bore bright actually remove metal?

p_083065100_1.jpg


or



p_083065025_1.jpg





 
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Kball, my point is that neither is going to remove metal from a modern steel barrel. The, "For the removal of lead, metal and powder fouling..." means gilding metal from a jacketed round, NOT the barrel itself. Using JB Bore Bright makes me feel better for trying harder than any tangible results given, so to start just try the standard JB. Bore Bright is great for mirror finising shotgun bores, if you're interested in doing that.

Simpler still; the one with the blue writing.


 
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400 to 600 grit finishes have been stated many times by educated barrel reworkers as ideal for air gun pellets / soft lead.

All one needs to really FEEL a barrel is with a hard rod and round jag tip with a dry snug patch is push a few from both ends and take note the friction difference.

Most barrels will indeed exhibit a near shark skin bias for direction and this should be smoothed out via some lapping compound more aggressive than a polish.



Been there, still do & will continue too ....



JMO tho and if unsure DON'T leaving it to someone more experienced

400-6oo grit is for LAPPING. Polish is best done with JB bore paste or JB polish. Also Butch’s boreshine … these clean and polish.

A rough or uneven bore can be improved by judicious lapping, but an already good, but dirty or fouled one should be polished.
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In my somewhat limited experience... You can.

Back in the early nineties, I'd picked up a QB-77 from Tim (at Mac-1) right after he started importing them and he mentioned that lapping the bore could improve the rifle's accuracy. So I picked up some jewelers rouge and soaked a few cleaning pellet with it. Firing one of those through a couple of times and following it up with ten pellets, then cleaning the barrel thoroughly did the trick (after repeating the process three times). It reduced the group size from ".25 to ".10 at ten yards and I was very happy.

When he got the new QB-22 in stock, I picked one of those up and did the same thing with the opposite results. The groups went from ".5 at ten yards to ".75. So not all barrels respond well to lapping.

J~
 
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I use Brownells and Wheelers bore lapping compounds on PB guns but have only used JB bore paste and a generic metal polish like flitz but 1/10th the cost on airguns.

I use a push/pull patch system that allows bidirectional polishing. The value of this system is no need for swabs, no metallic rods or ferrules and the ability to "saw" through burrs that need to be broken off, then polished.

Wheelers is 400, 600 and 800 grit while the Brownells is only 600 and 800. I find the Brownells to tear out material very fast but is harder to clean out.

I generally use the Wheeler 800 grit to remove the Brownells and JB paste to remove the Wheelers.

In airguns, I just use JB, I've not had to be more aggressive.

As far as over lapping, yes. Over polishing? I doubt it.
 
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Reg Creep said:
Thanks for sharing! Want to make sure I'm understanding correctly.
You are suggesting to use 400 and/or 600, but nothing finer?
A little texture is better than a super smooth finish?
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400 or even 600 when worked against the barrel steel leaves a very polished finish, tho not necessarily shiny, which you really don't want either.
 
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I've tried polishing a couple airgun barrels with JBs but it didn't seem to make any difference. I got my son a boroscope for his birthday and I plan to borrow it after a few months to get a look at my barrels and I might even get a before and after look with a polish in between. I was surprised the boroscope was well under $100. I might even get one of my own.

I think making sure there are not obvious chatter marks on the crown is important, however. I like my SPA rifles but their crowns looked pretty bad when I got them. I few minutes with a brass round head screw coated with JBs smoothed them up. But that also shows JBs will cut steel.

I sharpen my knives with a worksharp knife sharpener and my chisels and plane blades with a different worksharp. They use sandpaper to do the sharpening. I think the sandpaper is more aggressive than the abrasive in JBs but it is another example of abrasives cutting steel. I am comfortable that hand polishing with JBs won't remove enough to hurt a barrel but if you start using power tools it makes the possibility of removing too much more real. Without much experience I would want a boroscope or another way to see what was happening. 400-600 sandpaper will put a nice edge on a knife.
 
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