Can This No. 4 Barrel Be Saved? (Or Is It Me...)

So. A bunch of years ago I bought a No. 4 Mk. 2 because the numbers matched, but it sat in the back of the safe ever since. Pulled it out this week to clean it up and maybe shoot it a bit over the Christmas-New Year break. (Yup, I should have cleaned it up when I first bought it but was extremely busy at the time (excuses, excuses) and anyway that's water over the dam).

The exterior actually looks to be in good-excellent shape. The bore is a different story.

Based on advice from somebody on this site I bought a bottle of Patch-Out liquid because it seemed possible the barrel could have some copper fouling; in any case better safe than sorry.

Day #1: Ran a wet patch through and it came out bright darkish blue. Kept running patches through (about 15) and although decreasingly bright were still distinctly blue. Switched to nylon bore brush; back and forth five times, then followed with a patch wet with Patch-Out. O.M.G. The patch was absolutely black--almost muddy. Not good.

Fifteen more wet patches through and although no longer muddy, still had some blue color. Let's try the nylon brush again...EXACTLY the same result as before: muddy black patch with blue at the edges. This is the place for a well-known military technical acronym: C. R. A. P.

Repeat cycle three more times; same results each time.

Night #1: Run patch well soaked with Patch-Out and let it soak overnight (about nine hours).

Day #2: Replay of Day #1, except in between running wet patches 1) ran the nylon brush through five times each way--still got a muddy black/blue wet patch out right after. 2) After another iteration of wet patches, switched to a brass brush--got a REALLY muddy black wet patch out right after. Repeated wet patches--brass brush routine twice more, with EXACTLY the same result each time: muddy black wet patch right after.

Night #2: Well-soaked patch through to soak overnight again.

Day #3: Exact repeat of Day #2, except used only brass brush each time in between wet patches.

Night #3: TWO well-soaked patches to soak for 24 hours.

Night #4: 24 hours after last wetting with Patch-Out, ZERO change from the very first time I ran a patch through this barrel. Bright blue if Patch-Out only, and muddy black with dark blue edges after brass brush runs. I've now used almost half a bottle of Patch-Out and way over a hundred patches, so I'm out of ideas.

I don't have a borescope, and don't see any point posting pics of the patches or the towels used to wipe down the cleaning rod after each pass (although I can if you'll think they'll help).

I acknowledge the distinct possibility of operator error, so am I doing something silly here? I've cleaned a reasonable number of rifle and pistol barrels over the decades, and even the range rifles they gave us pilots on range day were not even close to this dirty.

You guys are the Subject Matter Experts, so I'm all ears (actually, eyes).

Sounds like it's still filthy. Even if the bore is completely ratholed out, once you get the crap out it'll be clean. Just done for. I had a Winchester I could clean until it had shine and the next day it would come through dirty again. Once it was clean it would show clean. Once it sweats out again you repeat.

Yep. Bores, especially when pitted, can hold a lot of nastiness. Layer after layer of copper and powder fouling, then rust. Hopefully you're not at .35 cal when mostly clear.

I have seen several others post that after the first cleaning, go out and shoot as that may actually remove or loosen some of that old nasty fouling. That has worked for me in the past and it can't hurt the gun either.

Time to go and shoot it. Twenty to thirty rounds should remove a lot of rubbish.

i could be wrong, but it sounds like there could be lead deposits in your rifling. Could that fit?

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Originally Posted by RobD

lead deposits

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This...

If you want to see if your barrel is still in spec. Go to APEX gun parts and buy the correct gauges to check it with. I've cleaned many LE barrels over the years and the majority will be just as yours unless they've never seen service. Heavily fouled and with brown/black fouling-rust. If the rifling is still decent and in spec, you'll be surprised that they will still perform on the range. This is the simplified WW2 specification and appropriate gauges.

.307 plug - must not enter the muzzle more than .25"
.310 plug - must not neter the breech more than .25"
.301 plug - must run through the barrel with no resistance.

Everyone who worries about their barrels in LE rifles should have these gauges in their tool kit. They will tell you pdq if your barrel is worth saving or scrap.

There is a very good reason that actual military operators of these items were keen on BOILING WATER, generously funneled down the barrel, preferably as soon as possible after firing.

Only a couple of caveats:

1. Using the correct funnel in the correct way and NEVER letting the hot water get into the woodwork, unless you want to get really adventurous and strip off the fore-end to dry it out and re-grease the metalwork.

2. Dry the bore with a CLEAN patch as soon as the boiling water stops coming out of the muzzle "discoloured..

3, IMMEDIATELY swab some oil through the bore while the barrel is still hot.

4. A couple of days later, do another "conventional" clean. This may show up a bit more jacket streaks and some dark propellant residue. This why we do a "follow-up" clean.

Yes, "modern" commercial ammo uses "non-corrosive" primers, BUT, slow corrosion can start, especially if you live in a humid part of the world, like coastal Florida or Queensland, etc.

The "old-timers / military users were intimately familiar with the evil residues from the issue ammo; (mostly hideously corrosive salts from the residue of the primer.

Once the rifling is "pitted", it will scrape off a lot more bullet-jacket material and this will also seal in little pockets of that corrosive residue.

I agree with all of the above. The barrel is only scrap when it is thoroughly clean and scrap. Even then, be advised that because a barrel looks like a sewer pipe doesn't mean that it won't be accurate. No4T's were a good example of this. Occasionally you'd get one that looked like a sewer pipe that shot absolutelt perfectly and accurately, So much so, thee sniper (who always had the last word, as his riifle was a personal issue to him) would tell you - in words that you would quickly understand - that it was perfect. While others would be all over the place and fail even the most basic accuracy test

When you start to scrub the barrel, make sure that you're only taking the crap out and not the bore out! We used to use a pink coloured tablet mixed with water (?) called KNS tablets - for Cupro-Nickel solvent. Any old Armourers out there remember using KNS tablets? I didn't see them in Oz but we did have them in NZ

L96's were a good example of where a new barrel could shoot worse that a new barrel. Don't ask me why. Some say a change of manufacturers from XX to XXXXX XXXXXXX. But even that assumption was never proven.

Well, it's too cheap now not to have one these days.
https://www.amazon.com/Teslong-Bores.../dp/B07XDYN296
There is also a flexible one that is great for carrying on your person and talking down prices at gunshows. The cheap one just requires a phone or laptop. There is a more expensive model with it's own dedicated screen.

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Originally Posted by Peter Laidler

I agree with all of the above. The barrel is only scrap when it is thoroughly clean and scrap. Even then, be advised that because a barrel looks like a sewer pipe doesn't mean that it won't be accurate. No4T's were a good example of this. Occasionally you'd get one that looked like a sewer pipe that shot absolutelt perfectly and accurately, So much so, thee sniper (who always had the last word, as his riifle was a personal issue to him) would tell you - in words that you would quickly understand - that it was perfect. While others would be all over the place and fail even the most basic accuracy test

When you start to scrub the barrel, make sure that you're only taking the crap out and not the bore out! We used to use a pink coloured tablet mixed with water (?) called KNS tablets - for Cupro-Nickel solvent. Any old Armourers out there remember using KNS tablets? I didn't see them in Oz but we did have them in NZ

L96's were a good example of where a new barrel could shoot worse that a new barrel. Don't ask me why. Some say a change of manufacturers from XX to XXXXX XXXXXXX. But even that assumption was never proven.

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I though KNS tablets where to be dissolved in ammonia, did they also work in water?

I have never used or even seen them, my understand re ammonia is based on a transcription of Army Council Instruction 108/1939, February 1939. concerning cleaning description for vickers barrels

I have found that shooting and cleaning, shooting and cleaning, can really help when dealing with a neglected bore.
Generally speaking, a lot of issue ball of all calibers was made with cupronickel jackets. Nickel fouling is more difficult to remove. Copper fouling from guilding metal is easier. I wonder how many service rifles actually had metal fouling effectively removed?

I’ve been asking myself the same thing. After Peter’s comment I really want to find and try those KNS tablets.

Ammonia-based bore cleaners, like the classic, nasty-smelling "Sweets" is primarily for removing copper-based jacket fooling. Being water-based as well, it will also function as a cleanser to remove propellant / primer residue..

In a plain steel barrel, it can be left in the bore overnight. BIG caveat: It can react with some STAINLESS barrels and prolonged presence may result in a "frosty-looking" bore; tears before bed-time.

Ambient atmospheric humidity is an issue when there are ANY corrosive salts left in a bore.

We coastal chaps learned this lesson a LONG time ago Those who dwell and shoot in more arid areas have a bit more time up their sleeves, Those living in the "Great White North like Alaska and Canada, will be aware of teh lack of humidity when it gets properly cold; all the water vapour is lying, frozen, on the ground.

I remember reading somewhere that the trick, when operating in such conditions, was to leave rifles outside the comfy cabin. The reason given was, because once the well-chilled rifle came in from the cold, water vapour from the people, dogs, stove, etc, would condense on the cold metal and do its thing.

I've posted this story here before...I had a well-seasoned 1917 BSA SMLE that didn't so much group as pattern, like a shotgun.

I spent an entire winter off-season cleaning it, using foaming bore cleaner (left to sit for an hour or so), bristle brushes, and patches...I just kept going until the patches stopped coming out with any blue. I figured it probably hadn't been deep-cleaned since it left the factory, or at least since the Roaring Twenties.

Took it to the range the following spring and it grouped, very nicely.

---------- Post added at 05:26 PM ---------- Previous post was at 05:18 PM ----------

Was this sort of a pre-packaged version of "ammonia dope", a copper remover to be used only at rear echelons, and with great care?

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Originally Posted by enbloc8

I just kept going until the patches stopped coming out with any blue.

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And this story has been repeated through many caliber rifles...truth.

Always remember if using a brass jag your going to get a slight bluing of the cleaning fluid due to the copper content in the jag, I use aluminium ones if I'm in doubt as to the amount of copper if any in the barrel.
One that will rip it out is Montana Copper Killer just the health warnings alone on the bottle is enough to scare the copper out, Sweets Copper solvent is very good as well but be warmed if using it in a stainless barrel no more than 10 minutes in the tube then, remember to patch out with with metho to neutralise the solvent anytime you use copper a solvent.
Then oil the barrel.

Even Teflon-coated pistol bullets will "shed" in a less than "perfect" barrel. It usually indicates that the barrel itself is not nor, or maybe has never been 'stellar".

Teflon repels all chemical "boarders" and steady, but judicious work with a stainless-steel brush will remove it, but the underlying reason for the stripping of the Teflon, (a crappy barrel) will remain.

Anyone priced quality 9mm 1911 barrels and bushings, lately? And have the gear to properly mate an "unfitted" barrel and bushing to a slide and frame.. LOTS of variables being juggled, right there.

One more reason for chromed bores then? Though plating is generally only as good as the surface prep of course.

Final update. Christmas and family stuff put this project on the back burner, but I also needed to buy some additional stuff to finish the project.

What follows is not intended to change anybody's mind or suggest they change whatever cleaning regimen works for them. This is just what worked for me. This is a long post in the hope it might help someone who doesn't already have a self-proven cleaning regimen.

First, my general preference is to let chemistry do the work and avoid mechanical action as much as possible. My No. 4 Mk II is a little older than I am, and I have no idea who did what, how often, and how well in the past. I'm concerned about the lands and grooves remaining as intact as possible in a rifle this old. So for me, Patch-Out is is.

Because I continued to get muddy & blue patches with the Patch-Out, I called Terry Paul, owner of Sharp Shoot R, maker of Patch-Out and Accelerator. He was very friendly and extremely helpful, and pointed out a couple of things I was doing wrong.

First, he strongly recommends NOT using brushes at all, except for a nylon brush as described below. Absolutely no brass brushes.

Second, any brass tools used (cleaning rod, jag, brush, etc., will cause the patches to continue to come out blue until the cows come home because the Patch-Out is leaching copper from the brass tools. In computer programming terms this would be called an "endless loop."

Third, for an extremely dirty bore like mine that doesn't clean up with simple wet patches, he recommends using an Accelerator/Patch-Out mix to run a well-soaked NYLON brush on a fiberglass rod ONCE through the bore until the brush tip is barely out of the muzzle, then withdraw it. This causes the Patch-Out/Accelerator to foam in the bore, which results in a more thorough chemical cleaning.

In my case, with the bore as dirty as it was, I let this sit overnight. Next day I ran a clean patch on a plastic jag through the bore. It still came out a bit blackish with some blue. Repeated the process the next night and following morning. The second procedure resulted in a "clean" patch with no color.

Terry recommends that following a thorough cleaning resulting in a clean (no-color) patch, you do what he calls a "Proof Test." Run a patch well wetted with Patch-Out through the bore. Let it sit for 10 minutes. Run a clean, dry patch through. If the patch comes out clean, the bore is completely clean. If not, repeat the overnight process described above

I got a successful Proof Test, so on to the bore gauges. It was suggested I buy them from Apex, which I did, but I wish I'd done some checking first because they are $40 each there but 20% cheaper from brpguns.com. Oh well, got what I need, and the barrel specs perfectly per the gauges.

I haven't yet bought a bore scope so can't comment on erosion. Regardless, I'm not going to replace the barrel even if I have pitting.

So now I can reassemble the rifle and should have time to shoot it in a couple of weeks. Weather here has been summer-like but I'm too busy to step outside to shoot (I live in the mountains so no formal range needed!).

This was a long and more complex project than originally envisioned, but now I'm sure my bore is in good shape so we'll see how well it shoots.

Forgot to mention that after finishing the Patch-Out process, I ran 1/2 gallon of boiling water through the bore. Not sure that much was necessary, but I couldn't tell whether it was coming out "dirty" and the extra didn't cause a problem anyway (except the barrel and action was damnably hot!*). Should also mention the rifle was disassembled throughout this entire process.

After letting the metal cool, ran a final wet patch with Patch-Out followed by a dry patch to lube the bore.

Hope to reassemble the rifle today if time allows and shoot it in a week or two.

* Yeah--not kidding. If you run boiling water through a disassembled barrel, be sure to hold it with a thick towel or oven mitt. Ask me how I know...

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Originally Posted by tj214

If you run boiling water through a disassembled barrel, be sure to hold it with a thick towel or oven mitt. Ask me how I know

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That's why it was done though...expand the metal pores and boil out the salts. Done using the little bent funnel on issue, the wood was left on so no burns. Too, just a pint and a half(?) of boiling water after firing. I'm looking forward to hearing about yours after completion.

I'm a big fan of JB bore paste, as I'm not a believer that chemical cleaners can remove heavy or persistent fouling alone - especially after you invest in, and inspect your 'cleaned' bore with a bore scope.

With respect to undue wear caused by brushes and other mechanical means of agitating fouling - I think any of that is extremely minor when compared to sending bullet after bullet at ~2400 fps...

I've always been a fan of barrel soaking and it has worked well for me on several occasions. Buy or make an adequate chamber plug and fill the bore to the muzzle crown with the bore cleaner of your choice and let sit overnight. Much more effective than just wetting the bore with patches. I've had a couple of rifles that needed that treatment more than once.
Going to ask a silly question...are you sure that it's not a cosmolene stuffed barrel that you're working with as opposed to actual fouling?

Finally followed ssgross' advice on the Teslong USB Borescope (THANKS!) and now have a new toy to play with. Dead easy to set up and use on a MacBook Pro. The one at SSG's link is specifically USB and the manual says it works with Win XP/Vista/7/10 and Android, but I have no experience with them. Teslong sells other borescope versions for iPhones and other smartphones.

Took these pics after thorough cleaning with Patch-Out/Accelerator and boiling water. The barrel gauges perfectly with the bore gauges.

I have no experience with borescopes, so can anybody tell me what they see in these photos of my No. 4 Mk. 2? To me it looks like considerable pitting. The local "experts'" guesstimates are all over the place so once again I'm back to you Subject Matter Experts.

Attachment 129555Attachment 129556Attachment 129557Attachment 129558

You have a little pitting some carbon and a wiff of copper. JB or ISSO paste, mild scrub a good clean out with a carby or brake cleaner to remove all the paste, a light oil and you are good to go.
Keep on top of the carbon you now have the tool to do so.

doesn't look too bad. Be careful with your new toy. It will try to play tricks on you. Try taking the side mirror off - makes even a brand new mirror bright bore look pretty dull and crappy. It's just the angle though. birds-eye will show even the smallest amount of copper as a dull orange/brown (don't confuse with rust. rust shows as a dark brown). things that are hard to spot with the side mirror will jump out without it.

Third photo is rust scale IMHO. You might want to degrease the barrel with something like oven cleaner then fill with vinegar and let stand for a day and then scrub out with a stiff wire brush.

Makes me wonder where they got the ball bearings used in "ball burnishing" and whether a person could so something similar these days.

Anyone every try Evaporust on a barrel? Works wonders on old motorcycle parts to remove the rust.

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Originally Posted by Surpmil

Third photo is rust scale IMHO.

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Could be dingy colored oil too. Appears to have a slight translucence to it.
If it is surface rust, boiling in plain old water will convert it to magnetite (bluing). Then again, with so little - shoot your rifle and it will go away ;) Then care for it so it won't return. Take a pick with a birds eye (take the mirror off) of you new camera. If it's oil or grease, it will show up in different shades as you wipe a patch over it. If it's tarnished copper, it will show a dull but solid brown/orange. If it's rust, it will be a solid spot of dark brown. Carbon doesn't really show in the birds eye angle - shows black with the mirror, along with burnt on oil from firing.

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Originally Posted by Brian B

Anyone every try Evaporust on a barrel? Works wonders on old motorcycle parts to remove the rust.

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I've used it on parts before prepping for slow rust bluing before when going for an "antiqued" slow-rust blue effect. It will remove any and all bluing from anywhere it touches, even the accidental drop. I would never uses it if I cared to preserve anything left of the original finish. Boiling in water if you want preserve/conserve is the way to go. Lots of videos out there on this - a YouTube channel of "Anvil" by Mark Novak comes to mind. Cheaper than a jug of evaporust too - rain gutter section with end caps, a bit of jb weld to make the ends water tight, put it on your BBQ, in a bonfire, propane burner, whatever you got. Only need to boil 1-2 gallons of water to get the job done. Use a soft wire carding brush from Brownells (I think it's like $12 when I got mine, $25 for the very soft carding wheel to put on your motor), or just plain 0000 steel wool. evapo-rust is like $50 for the gallon jug. Gutter, caps, and steel wool are much, much cheaper.
One thing though, I did not scroll back up to see if your rifle has any suncorite paint on the exterior. Not sure how that will fair with any of the recommendations so far. Watch Mark Novak's conservation video. You'll be amazed at what comes out of the process with no refinishing, just boiling.

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Originally Posted by ssgross

Could be dingy colored oil too. Appears to have a slight translucence to it.

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I expect he's already run a brush down the bore a few times. ;)

I use 2 stroke synthetic engine oil for nasty bores. Wet the bore with patches, wait 20 minutes, scrub with plastic bore brush, patch clean. Repeat if nesasary.