Unconventional approaches to cleaning pitted bores 91/30's

[Rpower]

I'm doing a little experimentation with polishing mosin nagant barrels. Basically I have two or three of these rifles with fair bores I would like to smooth out a little to make it easier to clean and maybe more accurate. As a learning experience I used a cut section of scrap barrel 7" long as a test for some less typical techniques with promising results. This is what I have so far:

The original condition was soiled with good rifling. There were moderate sized streaks of baked in carbon/powder deposits soaked with WD40.
Wrapped some 0000 steel wool on nylon brush and with WD40 as a cleaning solution cleaned out the black in seconds.
Hit it up with some degreaser.
Next tried using some Nevr-Dull polishing cotton run through the bore using a jag one way only as described by one online source. Appearance brightened considerably but not exactly polished.
Next used some mother's mag and aluminum polish by hand with cotton swab. 40 passes made minimal difference.
Next put power drill on end of cleaning rod and rotated it through the bore section. seemed to clean up the lands a little but gave it all a circular swirl...not good for a barrel.
Played around for a while with these techniques, found things were increasingly smooth but far from clean. The pits became more obvious when seen from a side view (handy that the barrel was cut off, could see form inside that way) but looking much better when looking down the barrel itself with a light at the end.

The final stage was different and rather unconventional. The hand buffing was tedious so I managed to use two light/small vise grips to clamp the cleaning rod onto the long wood blade for my electric reciprocating saw and at half speed buffed the inside of the barrel back and forth with a cotton swab covered in mothers polish. Actually did smooth thing out fairly well but the swab compacted quickly and didn't force itself well into the grooves.

Overall it looks like an improvement but far from ideal.

If anyone has some good tips to improve the test process I'm keen to hear it. Right now I'm just trying to figure out how to better use the saw approach with something able to reach down into the grooves somehow. Brushes won't work as it changes direction every 2" of travel and so far the setup doesn't rotate with the rifling so it's just polishing the lands in line with the barrel (it's not following them).

Thoughts?

 

[boltonscouter]

From the sounds of it the are old war pigs so first thing, ditch the nylon brush and use a bronze brush. Wrap it once in a spiral with a cotton piece and soak in Hoppe's #9. Work it back & forth repeating until the rags come out reasonably clean. They might never come perfectly clean.
If you want to try lapping the barrel Google Tubb lapping bullets.
Midway shows actual ammo...........The Tubb Final Finish Bore Polishing Ammunition is comprised of a series of polishing compound impregnated bullets. Shooting several rounds of ammunition through with enhance accuracy by eliminating the imperfections inside the bore. Also makes the barrel much easier to clean. Bullet weights are approximate and will vary with compound. Each box contains 10 rounds of two different compounds.
You fire the 10 "coarse" rounds first followed by the "fine".
I also recall seeing boxes of 50 packs of just the bullets for reloaders.

 

[desporterizer]

You do realize the bore gets even bigger than it already is when you do all that lapping?

 

[boltonscouter]

found it ht t p://www.davidtubb.com/final-finish-bullet-kits problem is nothing .310 ...... just .308

 

[boltonscouter]

You do realize the bore gets even bigger than it already is when you do all that lapping?

True but it sounds like he's wanting to breathe new life into them and this might be a route especially if possibly shooting cast in the future but you're right...... it is a little on the drastic side.

 

[Ganderite]

Try fire lapping with lead bullets.

 

[desporterizer]

True but it sounds like he's wanting to breathe new life into them and this might be a route especially if possibly shooting cast in the future but you're right...... it is a little on the drastic side.

I have shot cast through sewer pipes with excellent results. You cant fix pitting & rubbing away the pits rubs away the bore.

 

[marc_j]

Before you resort to harsh abrasive techniques, you should try electrical cleaning. You can find lots of different posts on the internet about how to do it. Commercial units are fairly expensive (~$100.00) but you can do it for much less.

For 7.62 you can use a 3/16 or 1/4 steel rod from the hardware store ($5); some household ammonia ($3); and a 3/8 wooden dowel. You need a DC low voltage power supply. People have used various plug in battery charges, batteries etc. I used a laboratory power supply (because I have one) operating at 2 v. The truth is the process is pretty effective over quite a wide range of voltages and currents. Use the dowel to make the chamber plug. Taper it on a sander or grinder and soak it in water for a few minutes before use.

This type of cleaning can be surprisingly effective, or not very effective at all. The principle is that the ammonia dissolves the copper in the "crud" and then the copper is deposited on the electrically charged steel rod. If there is a lot of copper in the fouling then removing it makes the remaining carbon fouling porous and soft (like removing the mortar from a brick wall). If the fouling is mostly carbon with little or no copper this process is ineffective. You can't really tell what the composition of the fouling is except by using this method and gauging the result.

I've used this method on lots of milsurps with generally good results. You get a lot of satisfaction when you push 5 tar black patches out of the barrel at the end on this process - that is equal to about 50-100 grey ones - people who have cleaned the old fashion way will know what I mean. Every barrel I cleaned this way was better for it. Several went from dark sewer pipes with ill defined rifling to really beautiful bores with very little wear. Electrolytic cleaning is "standard" for any new milsurps I buy.

 

[buffdog]

NEVER use a power drill in a bore, even with "soft" brushes. The rotation can cut small nicks in the rifling CROSSWAYS to the bore and it will collect metal from fired bullets. The "soft" brushes can collect crud on them and act like an abrasive.

Run the cleaning materials lengthwise only.

 

[Beater]

ive had great luck with super fine valve grinding compound

 

[BCRider]

Your goal of cleaning and polishing the bore is a good concept. But you're doing just about all the worst possible methods. First off you should not use anything that rotates in the bore. You're not only missing the areas in the grooves, which are just as important as the lands, but the methods you are using with compressed brushes and patches are going to turn the raised lines of rifling from sharp edged and square to rounded over lumps that won't engrave the bullets as cleanly. Not only that but you're reducing the height of the rifling. And it's not all that much to begin with. By reducing the height you're even further reducing the ability of the rifling to engrave the bullet with enough of a bite to get the spin going in a clean manner.

Depending on how aggressively you've done your tricks so far you've either ruined the barrel you're working on or you are darn close to ruining it. It isn't enough to make it look shiny when you look in the bore. The shape of the rifling still needs to be crisp. And all the things you've listed are either doing nothing or too much of the wrong things.

Methods to look into are forming a few cast in place plugs and using that plugs as a lapping tool with a new plug used for each finer grade of lapping and polishing compound. Another is the fire lapping trick mentioned already. There's some good web sites out there with more details on both of these methods. Google for "fire lapping" and "lapping rifle barrel" to read about these methods.

And because of the possible damage you've done to the barrel you started with I'd set that one aside and start with a new barrel. The one you've already done may be salavable. But at this point it's an unknown and you'll want to do the better and more proper methods on an untouched barrel then apply them to the one you've already "bruised". If it works out then great. But it would be a bad idea to call the right methods good or poor if done on a barrel that may already be worn by the wrong methods you've used so far.

And with rifle barrels the idea of "less is more" is almost always the case. If your barrel is truly pitted by corrosion you'll never remove the pits until the bore is totally oversized. A pit is a pit and the only ways to be rid of them is to fill them in or cut down the material around it until the surrounding area is even with the very bottom of the worst pit. The first method is impossible in a rifle bore and the second will make the bore too large and wear away the rifling at the same time. So the alternative is to cut away at the edges of the pits so they are rounded and smooth. That way the bullets glide over the pits without any of the jacket metal cutting away and jamming in the pitting. Options like lapping and fire forming can do that.

 

[Rpower]

From the sounds of it the are old war pigs so first thing, ditch the nylon brush and use a bronze brush. Wrap it once in a spiral with a cotton piece and soak in Hoppe's #9. Work it back & forth repeating until the rags come out reasonably clean. They might never come perfectly clean.
If you want to try lapping the barrel Google Tubb lapping bullets.
Midway shows actual ammo...........The Tubb Final Finish Bore Polishing Ammunition is comprised of a series of polishing compound impregnated bullets. Shooting several rounds of ammunition through with enhance accuracy by eliminating the imperfections inside the bore. Also makes the barrel much easier to clean. Bullet weights are approximate and will vary with compound. Each box contains 10 rounds of two different compounds.
You fire the 10 "coarse" rounds first followed by the "fine".
I also recall seeing boxes of 50 packs of just the bullets for reloaders.

I do use brass brushes for aggressive cleaning but find they wear very quick on pitted bores as the bore acts like a cheese grater and rips em down fast. Nylon ones last longer and you can add fine steel wool to scrape out gunk in the holes, although wear effects is something of a concern. Good tip with the Tubb lapping bullets, I might try in the future but for the moment I'm looking more at light pit cleanup with mild bore wear. Thanks for the input.

 

[Rpower]

True but it sounds like he's wanting to breathe new life into them and this might be a route especially if possibly shooting cast in the future but you're right...... it is a little on the drastic side.

I am trying a few methods at the moment, mostly sticking to more controlled processes and I'm not set up for reloading even if the bullets were the correct size. Staged polishing processes seem promising, I'm talking really fine grits to smooth out micro pits and round out edges on the larger ones to make cleaning easier. I've heard whitening toothpastes work well too.

 

[RobertMcC]

I cleaned mine via mixture of tooth paste and bore solvent. Brass brush and a drill on low speed.

 

[Rpower]

Before you resort to harsh abrasive techniques, you should try electrical cleaning. You can find lots of different posts on the internet about how to do it. Commercial units are fairly expensive (~$100.00) but you can do it for much less.

For 7.62 you can use a 3/16 or 1/4 steel rod from the hardware store ($5); some household ammonia ($3); and a 3/8 wooden dowel. You need a DC low voltage power supply. People have used various plug in battery charges, batteries etc. I used a laboratory power supply (because I have one) operating at 2 v. The truth is the process is pretty effective over quite a wide range of voltages and currents. Use the dowel to make the chamber plug. Taper it on a sander or grinder and soak it in water for a few minutes before use.

This type of cleaning can be surprisingly effective, or not very effective at all. The principle is that the ammonia dissolves the copper in the "crud" and then the copper is deposited on the electrically charged steel rod. If there is a lot of copper in the fouling then removing it makes the remaining carbon fouling porous and soft (like removing the mortar from a brick wall). If the fouling is mostly carbon with little or no copper this process is ineffective. You can't really tell what the composition of the fouling is except by using this method and gauging the result.

I've used this method on lots of milsurps with generally good results. You get a lot of satisfaction when you push 5 tar black patches out of the barrel at the end on this process - that is equal to about 50-100 grey ones - people who have cleaned the old fashion way will know what I mean. Every barrel I cleaned this way was better for it. Several went from dark sewer pipes with ill defined rifling to really beautiful bores with very little wear. Electrolytic cleaning is "standard" for any new milsurps I buy.

I've heard of this process and agree it's fantastic for cleaning out dissimilar metals like copper and lead, actually did a thesis in a related field. As this is rust inside pits and cavities it won't work as has been pointed out. Actually the barrels in question are reasonably clean with about 10 minutes of brushing with WD-40 and nylon brushes (they eat brass, one brush lasts one cleaning) but I'm looking to bump them up from fair bores to good and try to reduce the cleaning while improving the condition at the base of the pits. I can guarantee that other than WD-40 seeping in there is no mechanical means of reaching the bottom of an enclosed pit in a steel tube.

 

[Rpower]

NEVER use a power drill in a bore, even with "soft" brushes. The rotation can cut small nicks in the rifling CROSSWAYS to the bore and it will collect metal from fired bullets. The "soft" brushes can collect crud on them and act like an abrasive.

Run the cleaning materials lengthwise only.

You're right about the use of a power drill being bad for bores. In my test it was on a cut off section of barrel, not an actual rifle so there's no real need to protect the geometry of the rifling. I did that one to see if the compound would actually clean up the surface which it did ok. Also it was one of those cotton swab ones so no points to scratch, just a big flat surface. I have heard about soft brushes collecting debris but with the brass eaten away so easily I figure using nylon and WD-40 as a cleaner is ok since the WD-40 should lubricate the gritty particles and maybe reduce wear...but who knows.

 

[Rpower]

ive had great luck with super fine valve grinding compound

I've heard good things about that. Just ordered Simichrome metal polish, Permatex 80037 valve grinding compound and CTA Tools 2219 Fine/Coarse lapping compound for experimentation. I'm thinking about rigging up my saws-all with some sort of oversized cotton swabs and running coarse to fine in very brief passes of the compounds to see how it works, probably ending in mothers polish and the Nevr-dull. I also read from one person that he uses Nevr-dull as his final step each cleaning in the end of a jag on his surplus with no ill effects long term.

 

[Rpower]

Your goal of cleaning and polishing the bore is a good concept. But you're doing just about all the worst possible methods. First off you should not use anything that rotates in the bore. You're not only missing the areas in the grooves, which are just as important as the lands, but the methods you are using with compressed brushes and patches are going to turn the raised lines of rifling from sharp edged and square to rounded over lumps that won't engrave the bullets as cleanly. Not only that but you're reducing the height of the rifling. And it's not all that much to begin with. By reducing the height you're even further reducing the ability of the rifling to engrave the bullet with enough of a bite to get the spin going in a clean manner.

Depending on how aggressively you've done your tricks so far you've either ruined the barrel you're working on or you are darn close to ruining it. It isn't enough to make it look shiny when you look in the bore. The shape of the rifling still needs to be crisp. And all the things you've listed are either doing nothing or too much of the wrong things.

Methods to look into are forming a few cast in place plugs and using that plugs as a lapping tool with a new plug used for each finer grade of lapping and polishing compound. Another is the fire lapping trick mentioned already. There's some good web sites out there with more details on both of these methods. Google for "fire lapping" and "lapping rifle barrel" to read about these methods.

And because of the possible damage you've done to the barrel you started with I'd set that one aside and start with a new barrel. The one you've already done may be salavable. But at this point it's an unknown and you'll want to do the better and more proper methods on an untouched barrel then apply them to the one you've already "bruised". If it works out then great. But it would be a bad idea to call the right methods good or poor if done on a barrel that may already be worn by the wrong methods you've used so far.

And with rifle barrels the idea of "less is more" is almost always the case. If your barrel is truly pitted by corrosion you'll never remove the pits until the bore is totally oversized. A pit is a pit and the only ways to be rid of them is to fill them in or cut down the material around it until the surrounding area is even with the very bottom of the worst pit. The first method is impossible in a rifle bore and the second will make the bore too large and wear away the rifling at the same time. So the alternative is to cut away at the edges of the pits so they are rounded and smooth. That way the bullets glide over the pits without any of the jacket metal cutting away and jamming in the pitting. Options like lapping and fire forming can do that.

Thanks for the input. Just to point it out, this isn't a barrel, it's a 7" section I have left over from a sporterizing project on a mosin, no functional rifle barrel has yet been touched...I like to try before I commit to the real deal

This particular rifle was in poor condition with scratched up wood, was a Russian refurb, was not ideally cleaned after corrosive use shooting 6 MOA with scope. The cut down version is 7" shorter in a plastic stock with long eye relief scope on solid dovetail style mount and now shoots 2.5 MOA on the crappiest chineese mosin ammo known to mankind...my sniper only shoots 2 MOA on this crap. Since the rifle needs the servicing what better way to get your feet wet than to tinker with the useless barrel piece before tackling the well shooting rifle.

Agreed, the test so far has been less than controlled, as I mentioned in the recent posts there were motivations on how things have been done so far. Keeping the rifling square is a concern of mine. Even hand lapping is cited as tending to round out those same edges, seems to be a risk of the task. Apparently factory lapped barrels start out oversized and are taken down to spec through lapping. I'm not keen on "fire lapping" as i don't yet reload and think it's considered an aggressive method by most forums. Light hand lapping may be in my future and I have suitable coarse/fine lapping compound coming in soon.

Based on your comments and the comments of the other posters to date (Thank you all) i think the next step will be to either try and rig up a ball bearing handled cleaning rod on the end of a saws all to force a oversize cotton pad in and out while following the bore to LIGHTLY buff the top edge off the pits to make cleaning easier (done on the barrel fragment I'm working with) or should that fail try the tedious hand lapping process using melted lead slugs and the compounds I have coming in the mail.

I will say, the neat thing of using a bore fragment (other than no penalties for failure) is that at the end I can cut it in half and see what the rifling in the middle looks like in terms of rounding etc. even do detailed measurements. Just wish I had pictures back from the start...images are in my brain only.

Thanks Everyone!

 

[diopter]

Heat up the barrel section with a hair dryer, to replicate a hot from firing barrel, then run a nylon bristle bore brush coated with grease a few times.
Run a patch to clean out out grease before repeating.
Try it, for say three times on different days and see what happens after the fourth day.

 

[BCRider]

....Just to point it out, this isn't a barrel, it's a 7" section I have left over from a sporterizing project on a mosin, no functional rifle barrel has yet been touched...I like to try before I commit to the real deal

Oops, I think I missed that. I saw your mentioning of barrel sections but it seemed from the post that you were doing both in parallel. Good move on working with a hunk of "tubing" first.

The hand lapping isn't that bad. You would not be working the lead slugs long enough on any one grit in any event. If you DID stick with it long enough to make it tedious then you're working the bores TOO much and opening them up too much.

The nice thing about a cast in place slug as a lapping form is that you don't put undue pressure on the edges and cause them to dull over like you will with a tight fitting patch.

Now I freely admit that by the time you start and finish you're looking at a full on day to make up the cast lapping plugs and then work them through then finish with something like JB Bore Paste and the snug patches. But really a single day to obtain a life long shooter isn't that bad an investment of time.

Be sure you thoroughly clean the bore first as well. I was shocked at how much black and green came out of my re-furbed Mosins. They were dull looking as hell at first. But by the time I'd used a good amount of solvent and a half a can of Wipe Out copper foam and worn out two bore brushes each on the barrels I was seeing shiny looking clean rifling staring back at me.

Mind you I then shot two paper packs of milsurp copper washed ammo through them and I was back to square one again. I've now decided that I'm going to load up some proper copper jacket home loaded ammo and try both with laboriously cleaned barrels to see which shoots my home made loads the best. That one will never see milsurp ammo every again. The other will be used for casual shoulder thumping with the rest of the milsurp junk I've got. As in I've seen shotguns that can pattern better at 50 yards than this ammo give me from either rifle. Once the milsurp is gone it's good homemade loads that uses proper jacketed ammo and brass casings. No more milsurp for me. It's too variable and simply frustrating to end up with a SPAM can of crappy shooting ammo.