Cleaning a Mosin Nagant barrel

[19-3Ben]

When i had my C&R license and I was buying a lot of milsurp, I actually went down to goodwill and bought a pot for the sole purpose of boiling rifle parts. Worked like a charm.

 

[BCRider]

A lot of the replies are jumping around and talking about different things.

The bag and sun trick or using a heat gun is for sweating the cosmoline out of the wood.

The hot water is GENERALLY for cleaning after shooting corrosive primer ammo. Although I suppose it could work to some extent for cosmoline in the bore. It would be a slow way to do it though.

I would not shoot out the cosmoline. It's usually thick enough that it could act like a plugged bore. At the very least the peak pressure for the first couple of rounds would jump to well over SAMMI maximum allowances!

Alcohol hardly touches cosmoline. You want mineral spirits, Varsol, low odor paint thinner or even lacquer thinner. The last being VERY flammable and having toxic fumes so use outdoors and away from any flames or sparks. Besides, alcohol is THE SOLVENT for melting shellac. So if you want to keep the finish on the wood looking fairly stock then don't let alcohol anywhere near.

I found that the two I've got were in the cosmoline for so many years that the shellac simply flaked off from the rub down to get the cosmoline off. It kept flaking during the plastic bag sweating sessions too. In the end it was so spotty I gave up and stripped it all off and refinished with boiled linseed oil.

Plan on wearing out at least one bronze bore brush. You'll run the brush 10 to 12 times, then patch out the goop until the patches are clean. If you run the brush another dozen times you'll get a whole extra batch of goop coming out on the patches. I wore out three brushes cleaning two Mosin barrels until after brushing the patches came out only light grey. But the bores went from dark to shiny. So the cost and elbow grease was worth it.

There's most likely also a lot of copper fouling. Again, you'll go through a lot of the copper solvent of choice. That darn flashed plating on the steel jacket bullets comes off just way too easily.

You'll also want to get a couple of different bore brushes for cleaning the chamber using a rod extension and a hand drill. Lots of stories to indicate that the sticky bolt issue is due to packed and dried cosmoline on the chamber walls forming a lock.

 

[dmurdach]

I actually used the heat gun on all the metal parts as well, it doesn't take much to melt the cosmoline and then just soak it up as it melts. On the barrel i just get it warm to the touch and start running patches through. Re warm the barrel as needed until the patches come out clean.

 

[19-3Ben]

BCRider- I actually boil the metal bits of the guns to get the cosmo out. Once you heat up cosmo it melts and becomes highly viscous. Being a waxy/oily substance, it is lighter that water, and when submerged, will float to the surface. I have even gone so far as to take the bolt apart and take all the bits and throw them in the boiling water, then put them in my convection toaster oven at 250 degrees for 45 minutes to let the hot air circulate all around it and dry out the nooks and crannies.

Mineral spirits will thin the cosmo much as it does with other oil based goo. But heat is another way to make the cosmo much easier to work with.

I've found that using heat to get the bulk of the cosmo, and then mineral spirits to thin and wipe up the rest of the surface haze of it makes for relatively quick work of an otherwise laborious task.

 

[stonecutter2]

First, heat the barrel a bit with a blow dryer, or leave it out in the sun on a warm day. It will melt up and soften the cosmoline in the barrel. Might bleed some out of the stock, too.

Then run a patch through to get most of the initial gunk out.

Now get really hot water (not boiling necessarily), a bucket, and a turkey baster. Don't use your wife's Thanksgiving baster, buy a $1.50 cheap jobber at the grocery store dedicated for the job since it'll be going into the chamber a bit.

Suck water up into the baster, turn it bulb down, aim carefully into the barrel in the breech and put the muzzle in the bucket. Up end the baster and squeeze. Give it about 30 seconds, repeat. Now run another patch through to soak up/push out more cosmoline. Using mineral spirits on the patch gets even more of it out fast. Repeat until the patches aren't gross anymore. Then oil well.

After a range session with corrosive ammo, you can also then easily and neatly pour water through the barrel into the bucket to get rid of the salts and keep your barrel in good shape.

The dangers of windex, acetone, or kerosene is that they can spill on your stock and remove finish or at least mess it up. Alcohol will strip the shellac off. Not positive about mineral spirits...that would just strip the oils out of the stock if anything, probably.

 

[dmurdach]

oops

 

[stonecutter2]

A lot of the replies are jumping around and talking about different things.

The bag and sun trick or using a heat gun is for sweating the cosmoline out of the wood.

The hot water is GENERALLY for cleaning after shooting corrosive primer ammo. Although I suppose it could work to some extent for cosmoline in the bore. It would be a slow way to do it though.

I would not shoot out the cosmoline. It's usually thick enough that it could act like a plugged bore. At the very least the peak pressure for the first couple of rounds would jump to well over SAMMI maximum allowances!

Alcohol hardly touches cosmoline. You want mineral spirits, Varsol, low odor paint thinner or even lacquer thinner. The last being VERY flammable and having toxic fumes so use outdoors and away from any flames or sparks. Besides, alcohol is THE SOLVENT for melting shellac. So if you want to keep the finish on the wood looking fairly stock then don't let alcohol anywhere near.

I found that the two I've got were in the cosmoline for so many years that the shellac simply flaked off from the rub down to get the cosmoline off. It kept flaking during the plastic bag sweating sessions too. In the end it was so spotty I gave up and stripped it all off and refinished with boiled linseed oil.

Plan on wearing out at least one bronze bore brush. You'll run the brush 10 to 12 times, then patch out the goop until the patches are clean. If you run the brush another dozen times you'll get a whole extra batch of goop coming out on the patches. I wore out three brushes cleaning two Mosin barrels until after brushing the patches came out only light grey. But the bores went from dark to shiny. So the cost and elbow grease was worth it.

There's most likely also a lot of copper fouling. Again, you'll go through a lot of the copper solvent of choice. That darn flashed plating on the steel jacket bullets comes off just way too easily.

You'll also want to get a couple of different bore brushes for cleaning the chamber using a rod extension and a hand drill. Lots of stories to indicate that the sticky bolt issue is due to packed and dried cosmoline on the chamber walls forming a lock.

Agreed, never shoot out cosmoline. Anything in the bore can be an obstruction. Great way to potentially destroy a milsurp on the first shot.

You are spot on with mineral spirits, but I like to use it sparingly and use hot water to soften/melt the cosmo and get it out.

Not sure I'd scrub a barrel that much with a brush, not that I think the brush would do much damage - but perhaps the metal coil or base over that many times could be nicking stuff that I'd rather it not. I tend to take a less aggressive approach to cleaning, though.

 

[lencac]

I must say I'm amazed how much attention any type of Mosin question garners.
Plug the muzzle, stand the rifle vertically, muzzle down, fill the barrel with break clean and let sit for a few days. Then everything comes out easy as pie.