Cleaning rust out of a Mosin bore

[monotonous_iterancy]

A few weeks ago, I took the action out of my Mosin Nagant, and shined a flashlight down the barrel. I noticed some rust in the bore. I've never done rust removal on the inside of a firearm before. Is it necessary to remove it? And if so, what's the best way to do it without scratching or wearing down the bore?

 

[Cosmoline]

You can't really tell how bad the situation is until you get in there and use some elbow grease to remove it. Unfortunately when you have visible rust in a lot of old surplus rifle bores, there's a fair chance that's just the tip of the iceberg. Once you get rid of that, clean it and remove the copper, you may start uncovering deep pock marks where the rust has been slowly chewing away at the steel for decades.

But then again in some climates the stuff just grows on steel all the time, and will come right off with no real damage done.

As far as the method, just the usual rod with a brush and good cleaning agents. Personally I start with a blast of M-pro, clean that out, then go with bore gel, then finish with a copper remover. Alternate between brushing and swiping cleaning pads. I monitor patch color to tell me when to switch. The m-pro spray gets the first black crud out, then starts coming out clean. Then bore gel gets the grey crud out. Then brass remover gets the green crud out. A bore guide will keep the crown from getting hurt. You won't hurt it doing that.

 

[DoubleMag]

Blue Wonder makes a gel in a squeeze tube that will take out rust. How bad it is, no way of knowing just like Cos**** said. But this stuff works.

Good luck and have a great Holiday

 

[Slamfire]

Pray it is a light surface rust.

I have a M98 Russian capture. It is so rusted that you can see the bore change after cleaning. I think it is going up the barrel with each shot.

Have not fired the thing in a while.

 

[ball3006]

It is a whole lot easier to just remove the bolt to check the bore on a Mosin Nagant. Open the bolt and pull the trigger back and the bolt comes right out. Remember, surplus ammo has corrosive primers and you need to clean every time you are done shooting.....chris3

 

[monotonous_iterancy]

That's what I meant when I said "action", sorry for not being clearer. I've never shot surplus ammo through it, I always make sure to use non corrosive stuff. This rust could just be storage rust, from seasonal exposure. Hopefully that's what it is, and not some deep seated pitting.

 

[headoftheholler]

Any automotive parts store sells Naval Jelly. You can put it on a patch (avoiding the bluing on the outside) run it through, let it sit for a minute and patch out, repeat until rust is gone.

 

[Redlg155]

whatever you do, avoid the temptation of spinning a stainless steel "tornado" brush on the end of a drill bit. I knew a guy who would take a Mosin or other milsurp, spin brush through the bore, put a clearcoat on the stock and mark it up $100 plus.

 

[caribou]

If your shooting Corrosively primed ammo, simply use boiling water poured down the barrel, a very common cleaning stepfor all militarys that have/do use corrosive primeing. The water will dissolve and flush the corrosive primeings salts out of the bore. A good scrub and a rinse with boiling water , the heat of the now clean steel will dry itself, and after that simple step , clean with solvent, patches and a wipe of oil over the bare metal bore when finished.

If your not useing corrosive ammo and the bore is still rusting, its most likely a Humidity problem while stored.
Youll need to wipe a heavy oil down the bore after the cleaning to 'seal' the bare metal bore from the elements.
I usually wipe the oil out with a patch before shooting it.

As for Rust removal, soapy water and a boiling water rinse scrub with a good stiff brush will help get you down to the steel, solvents and copper/lead removeing agants afterward will show you what you got till your patches come out clean..............some rifles have problem spots, and all the scrubbing in the world wont help, but if its accurate, theres not much you can do but use it well .

I use a 20 gauge brush on the chamber, with a solvent or boiling water to remove any crud, cosmo, corrosion or carbon. This keeps the "Stick Bolt" away that arrives with dirt, laquer, neglect and such getting pounded in the highly pressured and hot chamber till its built up, "sticky" and hard to open. On a brand new rifle I use brake cleaner and free the chamber of all preservative, 60+ year old, dried cosmoline that actually looks like the steel. A clean chamber is a smooth operating Mosin. This is one place I will chuck the rod segmant from my home cleaning kit into a cordless and twirl the chamber from the breech end. After the first chamber scrub, all others are easy.

Power Twirling a brush down your bore will leave you with the sides of the lands uncleaned, so slow strokes down the bore with a rod or tip that rotates with the rifleing is the best method. It will ruin your metal brushes very quickly too.

If your Mosin came with a Soviet cleaning kit, it will have a muzzle cap with a hole, a connection peice to slide over the end of the rod and a small metal rod to make a handle out of. This will allow you to attach a brush and 'pump' the rod back and forth from the muzzle, wipe with patches and oil the bore without touching your muzzles crown, and then a chamber scrub from the breech.
Finnish cleaning kits have an extention to scrub the barrel from the breech.

Anyway you clean it, it must be thorough, not damage the bore or muzzle and some protection for the clean steel and you should have that rifle for the rest of your life.

Good luck and Good shooting.

 

[BCRider]

Unless you're seeing the tell tale reddish brown of rust I've found that it's not that easy to tell rust from lead or copper buildups. For the time being I'd treat it as lead or copper depending on what rounds you're shooting. Since you're reloading your own or buying modern factory I'll assume it could be copper fouling. Use a good copper cleaner and if the stuff comes out the telltale blue-green you likely found the culprit. If it is still rough looking after the copper cleaner doesn't come out coloured then it could be rust or it could be lead. At that point a bronze brush and regular cleaning solvent will do a pretty good job on either.

If it's still rough looking then it's rust spots. But some rust is not the end of the barrel. Lots of rifles with dark to moderately pitted bores shoot just fine for accuracy. For it to really mess things up the rust would need to be up very close to the muzzle.

 

[monotonous_iterancy]

I shoot modern factory ammo. That's a good point about copper fouling. I hadn't considered that.

 

[caribou]

As well, you can also help a good cleaning along by actually shooting it, maybe 20 times in a fairly rapid fashon and then go at it , right there, with a good scrub with a slovent/bronze brush.

Thought I'd throw that in, it's worked for me before.

 

[pat701]

Copper bore brush put into a power drill, you will distroy the bore brush but get the rust out, may need more then one bore brush.