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

[tj214]

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.

[tj214]

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...

[browningautorifle]

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

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.

[Beltfed]

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...

[oldfoneguy]

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?

[tj214]

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.

[Bindi2]

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.

[ssgross]

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.

[Surpmil]

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.

[Brian B]

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