Barrel Pitting

['88Scrat]

Ok I need some advice here ASAP, cause frankly I'm kind of freaking out a little here.

I recently returned to my parents place for the holidays for a few days. I have some firearms with them including my Mosin Nagant, M48, and my 1894 Winchester. I have kept them here for a little over a year while we've been renovating our house.

I took them all out just to oil 'em up a bit and keep them maintained when I noticed that my 91/30s barrel had gone from nice and shiny to sewer pipe in a year! This was concerning enough but my M48 had also suffered somehow except oddly in the case of the M48 only the last 6 or so inches of the barrel had turned to sewer pipe, everything further back is still shiny like new according to my bore camera. The Winchester was fine.

This is perplexing for several reasons. Firstly I don't use corrosive ammo, EVER. In fact my friends give me crap for always paying extra to ensure I don't accidentally get some. Second, I know as cold fact that when these rifles were put into storage (a cool dry closet wrapped in cloth gun cases in this instance) they all had nice shiny bores. Since I've owned it the M48 has never been shot!? Third, why is the Winchester seemingly unaffected and the M48 only half so?

How can I avoid this in the future? I'm not sure what I would have done differently, all my firearms and cleaned and oiled/greased before being put into storage of any kind. This actually scares me a little because I have some milsurps that are worth a lot more than a $120 Mosin or even $200 M48.

[WarPig1976]

I don't know why your barrels rusted. I do know storing wooden stocked rifles in gun cases can be detrimental to the wood & metal finish, but that's for another thread.
For long term storage use a RIG "rust inhibiting grease" NOT oil on the metal.

[Oliver Sudden]

I've seen badly rusted guns, they were stored in cloth gun cases. Can't say why but guns stored with out being in cases of any kind are less likely to rust. If the closet is on a wall that is on the out side wall of the room tempitures will vary as the seasons change. And Rig is great inside and out for storage.

[T. O'Heir]

Greased, not oil. Wherever they were stored in Mom's house was not dry. The wrapping in cloth gun cases is the primary cause though.

[tangolima]

Hang an aluminum tag on the trigger guard.

-TL

Sent from my SM-G930T using Tapatalk

[Dfariswheel]

First, in my many years I can say that as far as I know, there's no such thing as a "dry closet".
They all seem to be damp and will rust metal and mildew leather and canvas.
Virtually every rusted rifle I've seen was stored in a closet and/or a fleece lined gun case or cloth bag.

Second, how do you KNOW the ammo you got is really non-corrosive?
Not so much these days but in the recent past people got ammo made over seas, especially in former Soviet Bloc ammo factories in which the production staff were a little too likely to use up some old corrosive primers in the commercial production.
Even if the box is marked "Non-Corrosive" and it's advertised as such, ALL foreign made ammo should be suspect until positively proven otherwise.
What makes me think you got corrosive primed ammo is that the military rifles rusted, the Winchester didn't.

To test, clean the barrel out so it's dry.
Pull a bullet from the suspect ammo and dump the powder.
Get a piece of sheet steel and polish it off with sand cloth to a bright finish, then degrease with lacquer thinner, Acetone, or 91% alcohol.
Load the primed case in the rifle, hold the muzzle a inch or so away from the clean sheet steel and fire the primer.
Keep an eye on the steel for a day or so in normal humidity.
If the plate quickly develops red rust..... The ammo IS corrosive.

What to do now that you have pitting.......
Go to Brownell's and buy a one-piece stainless steel cleaning rod.
NOT brass, not aluminum, not a bore snake, and not a screw-together rod.
Dewey stainless one-piece rods are sort of the default brand for most shooters.
Buy a brass button tip jag.
Buy a good bronze bore brush for each caliber.
Buy a jar of JB Bore Paste, or JB Bore Bright.

Use the brush and bore solvent to make about 10 passes through the bore to remove the surface rust.
Use the paste with the rod and cotton patches to polish out the remaining rust.
This will not remove pitting....nothing can "remove" pitting, pitting is forever.
The paste will remove the surface rust and shine the bore as well as possible.

DO NOT try to shoot the rust out. That can cause a KA-BOOM.

To store the guns so they will never rust again.....
Clean the bore before storage.
For military rifles, use hot water or a black powder bore cleaner.
Either will dissolve any corrosive primer residue.
Note that no modern bore solvent will dissolve and remove corrosive residue.
Only water or something that contains water will do.
Even Hoppe's #9 will no longer remove corrosive residue since the EPA made them change the formula.
Once the bore and bolt face are cleaned with water, then clean the bore with bore solvent and patches to remove carbon and copper fouling.
For modern civilian non-corrosive ammo use a standard bore solvent.

Once the bore is cleaned, dry thoroughly with a couple of patches, then apply a rust preventing lube.
Good ones are CLP Breakfree and the above mentioned RIG grease.
Both are known for excellent protection.

Again at Brownell's buy a "Bluguard" bag for each rifle.
Other sites sell the Z-Corr brand bags.
These bags contain a chemical that drives out oxygen and moisture that causes rust and replaces them with a vapor that surrounds the metal with a barrier that totally prevents rust for at least 10 years, and as much as 20 years.
This is how the military now store firearms. Unlike the old greases, the rifle can be removed from the bag, the bore wiped out and the rifle put directly into use.

As long as the bag is properly sealed and not compromised by nibbling mice or nosy family the guns will be in perfect condition for years and years.

https://www.brownells.com/gunsmith-t...prod42749.aspx

These bags can prevent rust even in a nice "dry closet".

[Unclenick]

Originally Posted by '88Scrat

This is perplexing for several reasons. Firstly I don't use corrosive ammo, EVER.

If I understand correctly, it is only the bores that have rusted, not the outsides of the guns. As Dfariswheel suggests, you THINK you aren't using corrosive ammo, but you may be. I had this problem with my M1A once. I bought a case of surplus ammo sold as non-corrosively primed. It turned out to have been made on contract to some unknown entity by Sellier & Bellot in 1982 when theirs was still an iron curtain country. I sent the ammo to use in the M1A in a class at Gunsite in 1993, and all seemed fine until about a month after I got home, when I got the rifle out and found a layer of fine rust all down the bore.

It took me some time to work out the cause. Sellier & Bellot, even before the Berlin wall fell, never cataloged any corrosive primers after the 1960's. I contacted them to get confirmation of that, but was told that contract ammunition was custom and if the contractor ordered them with a corrosive primer, they would have been arranged for. But their records from the iron curtain days were all warehoused in paper form, so they really didn't have a way to check from the lot number (on the wooden case it came in). So, for a time, I assumed that had been the problem—corrosive primers—even though, if you think about it, nobody I can think of would have reason to intentionally order corrosive primers as late as the 1980's. And this wasn't 7.62, either. The headstamp is .308, though it was Berdan primed.


It turns out there is more than one way to put a rusty skin on a steel cat

Then, later, the true cause revealed itself. When we see a rusted bore we assume corrosive priming is the cause. It is nasty stuff and the rust can be in knots and it can pit the bore badly, but the rust in mine was very fine and cleaning it out left no pits apparent to my borescope. It was much more like the fine rust left when you expose bare steel to nitric acid vapors and humidity, as was the method of creating fine rust for rust bluing in a steam cabinet, originally.

That should have clued me in sooner than it did. Corrosive priming isn't the only way ammo can be corrosive. At the time I used this ammunition there was trouble with occasional rounds producing too little gas to cycle the M1A, and those shots felt wimpy and impacted low. The ammo I hadn't sent to class stayed in my basement. A couple of years later I noticed verde gris on a few of the case necks in one corner. So, I did a pull-down and discovered there was serious powder breakdown going on. About a fifth of the pull-downs had powder (a stick powder) that had clumped and become oily looking and that had to be picked out rather than just poured out. The corroded cases had powder that smelled clearly of nitric acid.

So, it turns out you can have corrosive ammo with non-corrosive primers. It just has to have expired powder in it. The stuff I got surplus was probably surplused out exactly because that problem had been discovered, so, caveat emptor.

Assuming you had a similar issue, why it would rust one bore all the way and the other only partially probably just shows the humidity (also required for rust) only got high enough to cause it in that area of the bore; probably from the muzzle cooling faster than the rest of the gun during a temperature change.

The acid fume exposure probably is subject to the same cure corrosive priming is. You should use a bore cleaner like Bore Tech Eliminator or the KG products or Hoppe's Elite that is water-based and contains a lot of corrosion inhibitors (the Bore Tech products can be left in a bore to dry out without causing corrosion; I've done it, but their corrosion inhibitors handle it just fine).

[tobnpr]

Plastic bags, vacuum sealed, with VPCI is one way.

Lots of brands, here's one at Midway

https://www.midwayusa.com/product/10...storage-bag-55

Brownells sells metalized plastic bags (zero vapor transmission), with protectant tabs. At five bucks a rifle, the cheapest insurance you can get.


https://www.brownells.com/gunsmith-t...-prod1154.aspx

Main thing to remember is that rust can occur only when iron is exposed to oxygen. Take away the oxygen...it isn't possible for rust to form.