Bore Polishing (NOT firelapping!)

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Molly posted this 21 June 2008

I stumbled across another neat little trick that may interest the PP crowd.  It's a take-off from something I wrote up in more detail for the CBA Fouling Shot a while back, but here's the whole story in condensed form: Some time back I bought one of the unfired Yugo 8x57 Mausers because they were such bargains.  But when I got the cosmoline off of it, the bore was pretty rough.  Not rusted, not pitted, but it looked like it had been finished with sandpaper.  I didn't want to throw it away, and at the same time, I didn't want to pour coarse abrasives down a new barrel as was recomended for conventional firelapping.  I decided to try something a bit less radical, and used JB Compound on a bore mop to coat the bore of the rifle.  Then I fired a light jacketed bullet load, used the mop again, fired another light load, etc.  When I was done, the bore looked like a mirror, and without any noticable enlargement.  I wrote it up, and several people have tried it with excellent results. A recent discussion of various grades of paper for PPing and various PP lubes brought the experience back to mind, because I wondered if anyone appreciated the fact that TiO2 - added to make paper whiter - is also a very, very fine abrasive.  You can get the idea if you just walk over to the wall of your room and rub it with a nickle.  It'll generally look like you wrote on it with a pencil, becaue of the metal polished off the nickle by the TiO2 (& other pigments) in the pant.  I'm a retired paint chemist, and I knew about this, but just didn't make the connection before. Anyhow, my first thought was to wonder if anyone had noticed any polishing effect from ordinary PP lead bullets.  Then I put two and two together, and wondered what would happen if I 'lubricated' PP cast bullets with JB compound!  Just finger rub it into the PP after wrapping, drying and sizing.  Works great, and without all the trouble of the bore mop approach. I wasn't trying to develop a more accurate load, and didn't test for accuracy (I should have, but didn't.)  I was trying to test another approach for polishing bores, and I got that in spades.  FYI, I used a moderate load with wheelweight alloy in a 30-06.  Nothing fancy, but it worked fast, easily and well. So if you've got a rifle (or pistol for that matter) that's prone to fouling or leading, you might want to give this a try.  If you happen to have a bore that has been rusted, it MAY be possible to salvage it like this, using an appropriate grade of very fine abrasive polish.  I'd recommend that you steer well clear of the coarser abrasives often recomended for fire lapping.  For some reason, the very fine abrasives like JB compound seem quite effective here, and polished the bore of the Yugo M48 in about 5 or 6 shots.  I see no advantage to coarser abrasives, and I can see numerous potential problems they could cause. Of course, the usual caveats apply:  These results were obtained using components, equipment and techniques that will differ from yours, so approach this experimental procedure with great caution if you decide to evaluate it yourself.  NEVER use experimental procedures of this nature - or any nature - with maximum loads unless you work up very gradually because the interactive effects could produce dangerous pressure levels.  Since you are the only person controling most of the variables involved, you will have to accept full responsibility for the results of your judgement and practices. Regards, Molly

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jhalcott posted this 21 June 2008

Quite an interesting read there Molly. I have a bore that may get this treatment.

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Ken Campbell Iowa posted this 21 June 2008

Hi Molly... as usual, very interesting ideas.

However, consider the way abrasives/polishes work:  if you have little mountains in the barrel, ( which tear mountain size grooves from the sides of your bullets... ) you should select mountain sized grit to shear those mountain lumps off with. 

Then when the mountains are torn  away, you will find boulder sized lumps ... now you need boulder sized grit ... when done with that, you will find pebble sized lumps ... now you need pebble sized grit.

Now at last you are down to something that resembles a sandy plain ... and you can use your JB polish to make that plain look  real  shiny.

But using JB on those mountains in a rough barrel will only result in mountains that are very shiny... they will still tear mountain sized lead curls and build-up from the sides of your bullets.


Here is a list of equivalents, for shooters::

Mountain size grit::  Clover 250 Boulder grit ::  Clover 400 Pebble grit ::  Clover 800 Sand grit :: somewhere in Clover 1200 and JB ....  use only to help your cleaning rag grab onto loose pebbles ( lead molecules and powder fouling  )  , and also to put a chrome like finish on the lumps ... mainly to impress your buddies ... Back when I was dumb enough to shoot .22Rimfire, I bot a 40X that came with an very slightly offset (  factory ) chamber ... the engraved bullets showed a high land, very slightly (g) .... I shot about 5000 rounds of very expensive match ammo thru it , each  & every bullet dipped in JB compound .. at the end, it did never not ever shoot any better, and the high land was still ENTIRELY there.  Wow, did that stainless barrel bore shine tho.

( I set the chamber back about 1/4 inch and put in a  perfect ( for me ) 52D style chamber...   engraved up to the case, and evenly,  and increased scores about 50%, but still not a top shooter ... maybe too too slick and shiny? I now think that maybe .22 rimfires maybe become too slick and shiny from cleaning ... would a freshing out with 250 grit restore the original magic?  Let me know.

 FWIW, I then screwed in a hand lapped Douglas .22 barrel with a tight 52D chamber, and the rifle is now a top shooter.  Of course, breaking rule AAA, I then sold the rifle to finance me a pretty Sako .308 deer rifle ... ).

So-- what does the above prove?  absolutely nothing, just some far apart and maybe imaginery data points.  An Anecdote,  not an Anti-dote (g).

Trivia R Us, ken campbell, Iowa

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Molly posted this 21 June 2008

Hi Ken,

> ... consider the way abrasives/polishes work:  if you have little mountains in the barrel, you should select mountain sized grit to shear those mountain lumps off with.  > Then ... you will find boulder sized lumps ... now you need boulder sized grit ...

>  (then) you will find pebble sized lumps ... now you need pebble sized grit.

> Now you can use your JB polish

Gotta disagree Ken.  Not from a validity perspective, but from the perspective of objectives:  You seem to think I'm trying to develop a new way to ream a freshly bored barrel before I rifle it.  At least, that's the only place in the barrel making process that I'd expect to see roughness describable as 'mountainous'.

Not so.  My only interest is in making a good barrel even better.  If a bore is so rough that it takes 250 grit to smooth it up, I don't have much interest in it anyhow.  But if it seems like a good, though not outstanding bore, or one that just seems more subject to fouling than I am willing to accept, maybe a bit of smoothing will help.  At least, that is where I'm coming from.

> But using JB on those mountains in a rough barrel will only result in mountains that are very shiny... they will still tear mountain sized lead curls and build-up from the sides of your bullets.

Maybe so.  But it seems equally likely that the bullet will simply slide off the smoother 'mountain', should that be the end result of fine polishes instead of coarser abrasives.  After all, a rough file is a lot more effective at metal removal than a polished burnishing rod.  So maybe - just maybe - a polished lump would not remove metal as effectively as the original rough lump.  Not arguing, because I just don't know.  But from a logical perspective, I think it could be argued either way.

> Back when I was dumb enough to shoot .22Rimfire, I bot a 40X that came with an very slightly offset (  factory ) chamber ... the engraved bullets showed a high land, very slightly (g) .... I shot about 5000 rounds of very expensive match ammo thru it , each  & every bullet dipped in JB compound .. at the end, it did never not ever shoot any better, and the high land was still ENTIRELY there.  Wow, did that stainless barrel bore shine tho.

That's indeed interesting!  Did you ever clean the JB out and recondition the bore to see what kind of accuracy it would deliver AFTER being polished?  After all, JB has never been promoted as an accuracy enhancing bullet lubricant - at least not in my hearing.  I wonder if the polished and reconditioned bore would have done better if it weren't handicapped (for accuracy) by the abrasive?

Regards,

Molly

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Molly posted this 21 June 2008

jhalcott wrote: Quite an interesting read there Molly. I have a bore that may get this treatment.

Let us know what you do, and what kind of results you get, would you?  I think notes on both visual evaluations (before and after) and accuracy comparisons would be intensely interesting.

Molly

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jhalcott posted this 22 June 2008

I think I will use the VERY fine clover grit on a rag before I would SHOOT an abrasive covered bullet thru it. I HAVE used JB on a copper fouled 25-06 barreled that looked gold lined. It shot as bad as it looked. After many passes with the cleaning rod, and normal cleaning in between, the gun shoots much better. The one I now have my eye on ,is a .17 Remington 700BDL.  I have had it for some time. It is starting to loose accuracy and the bore is getting dark. Maybe the throat is gone, and MY eyes aren't what they were 20 years ago. I have JB,1000 and 1200 grit on hand,plus some others. We'll see what's up as soon as I get a 'rountuit!

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Molly posted this 22 June 2008

jhalcott wrote: I think I will use the VERY fine clover grit on a rag before I would SHOOT an abrasive covered bullet thru it. ... Well, your money, your gun, your choice.  But not me! 

To me, the advantage of a polish (not “abrasive") coated bullet is that it conforms to the bore, rather than expanding and compressing according to variations in diameter and smoothness.  The rag approach will (I think) simply polish all surfaces equally.  And take it from me, you'll do one heck of a lot of polishing before you get a visible effect.  Put some JB on a rag and start polishing a scrap of steel.  A friend of mine did exactly that once, and developed a Captain Queeg compulsiveness about it.  He told me it took several months before he saw any effect at all.  There is a REASON JB Compound is advertised as harmless to the bore of your rifle! 

Otoh, even JB Compound will provide observable results in a few shots when used with a bullet applicator.  Why the difference?  I don't know for sure, but I suspect it's because the pressures from buring gunpowder forcing the relatively hard bullet into the throat / rifling are so much higher than what my friend could generate with his fingers.  Or stated another way, pushing harder polishes faster.

Another advantage is that a bullet should tend to polish tight / rough spots more than loose spots, thus promoting a greater uniformity of the finished bore.  Once engraved, the bullet won't expand at loose spots to polish them as much as it affects the tight spots.  At least, that's what I'd expect.

I've been down the road of pouring lead laps and working them by hand too.  BELIEVE me, a few shots at the range is faster, cheaper and much less laborious.

Regards, Molly

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cityboy posted this 30 June 2008

Moly

I have spent a lot of time looking for your article on bore polishing but have been unable to find it. Can you tell me which issue it was in?

City boy

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Molly posted this 02 July 2008

cityboy wrote: Moly

I have spent a lot of time looking for your article on bore polishing but have been unable to find it. Can you tell me which issue it was in?

City boy

Hi Cityboy,

I'm sorry, but my back fouling shot issues cover roughly 18 or 20 inches on my bookshelf.  I simply don't have the time to go through all of them.  But let me suggest that you go to the CBA forum, and download their free index.  You should be able to track it down easily with that help.

Molly

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cityboy posted this 02 July 2008

Moly

I have the same problem as you, a big stack to go through. I checked the index and I can't your article.

City boy

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Molly posted this 02 July 2008

Cityboy,

Check your PM's/

Molly

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specops posted this 16 July 2008

Molly,

I've used a similar solution for my grandfathers Marlin 1897.  Even after a through scrubbing the bore looked like 20 miles of bad road.  I dipped the bullets from a box of standard velocity .22s in Fitz polish and loaded them one by one and fired them.  You could watch the groups shrink and the point of impact start to cluster where the sights were pointed.  It worked great and seems to leave a coating on the bore that makes cleaning much easier.  I have 2 Mauser M24s in 8 mm I'm thinking of trying it on but I may have to give the JB a try on one and see how it compares.

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Largom posted this 16 July 2008

Molly,  I am new to cast bullets and this may have already been tried, but why not

fill the lube grooves with JB or melt some lube and mix in abrasive grit of choice?

THANKS,  Larry

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Molly posted this 17 July 2008

Largom wrote: Molly,  I am new to cast bullets and this may have already been tried, but why not fill the lube grooves with JB or melt some lube and mix in abrasive grit of choice?

THANKS,  Larry

As far as filling the lube grooves with JB, it should work fine, but I just didn't try it:  I wanted to use as little work as possible, and already had other stuff on hand, ready to use.  (8mm Jacketed ammo, etc).  But filling lube grooves with JB is essentially what I did for the paper patched version, which worked swell.

(While recognizing that bullet lubes don't lube after all). I kinda hesitate to add abrasive to lube:  Most lubes PREVENT abrasion, while grit maximizes it.  And adding polishing grit to your lube isn't at all likely to enhance accuracy.  Besides, it brings other factors into play.  Do you want to go the messy hand-lube route, or put it through a luber-sizer?  If the latter, you'll have to deal with wear of the sizer die at the ver least, and it will probably be a lot more difficult to operate - if it can be operated at all.  And then, you have to get it all back OUT when you're done.  But hey, there's no really serious bar to any of the above as far as I know.  Give it a go, and post your results, OK?

Fellows, I'm sorry to announce that I will have to revert to an infrequent lurker mode for some time to come:  My wife went into the hospital yesteday afternoon with severe respiratory problems, and they're trying to get her into emergency surgery today.  They are trying to figure out exactly what sort of 'interstitial (?sp?) lung disease' she has.  If it's inflammatory, they can treat it with antibiotics.  If it's scarring, there isn't much they can do except keep her comfortable.  Either way, she's gonna need my support for some time to come.  And I have some entertaining medical conditions of my own.

I'll be back as opportunity permits, but not on a regular basis.

God Bless, Molly

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BruceV posted this 17 July 2008

I do not know you.  I have followed this thread with much interest.  It is with regret that I read of the health problems which your wife is facing.  Hopefully the physicians will be able to help her.  And hopefully you will see some improvement with your own medical conditions.  I will keep you both in my prayers.  God bless you.  Sincerely.  Bruce.

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Largom posted this 17 July 2008

Molly,  I am sure I speak for everyone when I say our prayers are with you and your wife. Please let us know the situation at your earliest oppertunity.

GOD BLESS,   Larry

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Molly posted this 09 August 2008

Well, I guess I'm back, at least to some extent.  My wife is much improved, thank God.  Where she literally couldn't walk across the living room without gasping for air and coughing her lungs out, she can now go for 20 or 30 minute walks. It is literally a gift from God.

Doctors say her lungs are full of scar tissue from a long persistent cough, and the scar tissue has built up to the point that she has a tough time inflating her lungs.  But they've got her on steroids, and as I said, she's getting around fine now, though she still ouches from the surgery (to get a sample of her lung tissue for diagnosis).  But the doctors say she should have a good 5 to maybe 10 years, and at our age, that's not really something to be concerned about.

Thanks for the prayers and the good wishes.

God Bless,

Molly

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BruceV posted this 09 August 2008

Thank you for letting everyone know how you and your wife are getting along!  You are and remain in our thoughts and prayers. 

Sincerely.  Bruce.

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amb1935 posted this 05 March 2010

I have on hand both Flitz and Mothers Mag polish. I see that someone has had good results with Flitz, but I was wondering if Mothers would be ok to use. I'm not really sure, but from personal experience in polishing I think that mothers is slightly more aggressive than flitz. Does anyone know for sure?

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Largom posted this 06 March 2010

            You can call it polish if you want but when you fire a bullet with any kind of abrasive on it you are fire-lapping. This thread is over 1 1/2 yr, old and during that time I have fire-lapped over a dozen barrels. All were inspected with a Hawkeye bore scope throughout the process. None of these bores were pitted but all showed various degree's of tooling marks. The abrasives used ranged from 320 grit to 1200 grit lapping compound with a final polish of JB. Since the lapping compound was all oil based I applied it to cast bullets by spreading on a flat metal plate. Using a second plate the cast bullet is rolled in the compound between the plates with moderate pressure. JB compound was applied in the same manner. No more than 5 bullets were fired and the bore cleaned and inspected with the borescope, then the next finer grit applied and the process repeated.

            I will add that most bores only got the 1200 grit and JB treatment, thats all they required. Every single barrel showed an improvement in accuracy. The most dramatic being a customer's Encore with a 260 Rem. barrel. This gun would barely shoot 4in. groups at 100 yds.I firelapped this barrel with 5 different grits including the JB. Off of my bench this gun then shot consistent 5/8 in. groups with jacketed bullets.

           This process can extend/lengthen the throat a small amount which can be a good thing with cast bullets.

 

                          Larry

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303Guy posted this 15 June 2010

There is something else that fire-lapping does to a bore - it gives it a slight taper.

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