Rust in mosin barrel.

[gfercaks33]

In one of my mosins it keeps getting a slight surface rust in the barrel. When clean it with the 30 cal brush it get 90% of it off but still leaves some. What can I use to kill all of the rust so it won't comeback. Mind you this gun sits with the rest if my guns and it is the only one that does this, I clean it and check it out after a while and I get a light coating. Should I try using a 8mm brush?

 

[Xombie75]

1. Are you using corrosive ammo? Not judging your intelligence but it's a valid question. If so you need to flush the bore with water really well to neutralize the salts before cleaning the bore. If you don't flush the salts out they sit under the oil and remain hygroscopic and continue to pull moisture from the air continuing the oxidization process. They can even hide and rust under copper, lead, and carbon fouling that remains in the bore. If you do flush with water and then don't dry well enough then coat with oil you also get rust. I've seen both situations from people familiar with corrosive ammo but didn't fully understand what it takes to keep their bore maintained when using it.

2. Is the barrel already frosted/pitted? If so you probably need to saturate your bore with synthetic high temp grease or eezox prior to storage. I use Automattenfett for K-31 rifles on all my mil surp bores after cleaning and prior to storage but that's hard to get in the US of A. I coat everything else in eezox to prevent any rust issues.

3. Finally do you have a dehumidifier in you safe? At least get a silica brick to absorb ambient moisture in your storage area. That will do wonders to combat rust in storage.

Someone who knows more than me may have better ideas. These are just my solutions based off the limited info from your question. Hope it helps.

 

[Coded-Dude]

Cream of tartar is good for removing rust, it is also good for cleaning brass. You can find recipes online.

Transmitted via Tactical Telecommunications Device

 

[gfercaks33]

Yes I'm using surplus ammo and I do neutralize the salts after. The rust appears only in one spot on the barrel which is odd.

Yes there us minor pitting.

 

[aestus]

So here's the thing with most mosin barrels. Unless you get a pre-war era mosin with pristine bore, it's most likely pitted and no matter how much you clean it's always going to be dirty. Over scrubbing it with brushes can actually do more damage than good and you could be making it worse.

Unless you cake the inside with cosmoline, it's going to rust. That's assuming you're actually able to scrub out the rust, otherwise the cosmoline will sitting on top of the rust inside the pitting and it'll rust anyways under the cosmoline. Rust in the barrel is going to be the fact of life, especially in a war era gun with a blackened bore. Best way to keep the rust out is to keep shooting it and oiling it afterwards

If you're not looking for long term storage, but want to shoot the gun occasionally like a couple times a year, then only other rust barrier I can recommend is the Frog Lube paste. Not the CLP, but the paste.

Heat the barrel nice and hot after cleaning with a heat gun and run the paste in the bore. The barrel should be hot enough to instantly melt the paste into a viscous oil and it should get everywhere and inside all the tiny pitting. Once it cools, now you have a solid waxy barrier that holds up better than any oil or CLP for rust protection besides heavy grease or cosmoline. It'll also be safe to shoot and after the first round, the bore will be wet with melted Frog Lube.

That's literally the only thing I use Frog Lube for is weapon storage for firearms I hardly shoot. Otherwise, I normally run a wet lube like Slip 2000 EWL. There's a few vids that shows just how great Frog Lube paste is at preventing rust VS all the other lubes. It's not because Frog Lube paste is anything magical, but because it cools to a solid waxy paste, which doesn't run and can't be washed off like more viscous oils and CLP. That's really the only reason why it performs better than an "oil" for rust prevention.

That being said... Is Frog Lube paste really worth it for a $100 rifle? The stuff is not exactly that cheap and seems overkill for a cheap surplus rifle...

 

[HiredHand]

To the OP, how are you cleaning the bore?

 

[gfercaks33]

Brush it and the patch it till they come out clean the a oil soaked patch down the pipe. I've done the boiling water down the pipe and I have also tried windex to neutralize the salts.

 

[HiredHand]

Are you using any type of bore cleaner or solvent?

 

[gfercaks33]

Hoppes 9 I probably need to switch to something better

 

[Shadowrider]

Sounds like it still has some corrosive salts embedded in the pits of that spot. This may be more work than the rifle is worth but here goes:

1) mix up some Ballistol with water (9 parts water to 1 part Ballistol)
2) brush the pizz out of the bore with this, don't be bashful with the mixture.
3) patch it dry.
4) plug the chamber with a rubber plug
5) put the gun muzzle up in an undisturbed corner somewhere and fill the barrel to the top with Kano Kroil cover the top balloon and rubber band.
6) leave it setting for a week.
7) pour the Kroil back in the can (it'll still be good and you'll need it below)
8) brush the pizz out of it again with Kroil
9) swab it dry.
10) using a jag, tight fitting patches, Kroil and JB bore paste run it back and forth, especially on this spot as many times as it takes.
11) clean it out with patches and Kroil, dry it out, and use Ballistol, Eezox or Frog Lube as a preservative like mentioned above.

Frog Lube does work well at preventing corrosion as does Eezox. But none of these new wonder lubes (or old ones) will remove the corrosion once it's there. Kroil and JB Bore paste will but it takes time and scrubbing. When you're done it might be the most accurate gun you own.