Cosmoline & ammo question?

[Alan Fud]

I just noticed that the inside of some of my magazines have cosmoline in them. Could this have negative impact on the reliability of the ammo? Also, how do I clean the inside of the mags?

 

[WardenWolf]

It won't damage the rounds, but certainly won't be good for the gun if it gets in the chamber or barrel before firing. To clean your magazine, take the floorplate off (on combloc rifle mags, there's usually a tab on the bottom of the floorplate; push that in and slide it off), pull the guts out (including the follower) and wipe them down. Then get a paper towel and run it through the mag body, bottom to top. Repeat until the mag is clean. Some people may advocate dropping it in mineral oil or the like, but this works perfectly fine and will give you a clean magazine in less than 5 minutes.

 

[stickhauler]

The answer to that whether it will hurt your ammo in some way really comes down to how long you plan to have it in a magazine. I've seen claims that oil will harm ammo, but have never seen or heard any absolute proof of that claim. I'd say it's bogus, most modern ammo (well, factory ammo anyway) would have the primers sealed in some manner. Cosmoline is only an oil based preservative, kind of like a runny grease compound.

As to how to clean the interior of your magazines, no matter what kind you have there has to be some method to disassemble them. Do that, soak them in mineral spirits and swab them out until they're dry.

Truthfully, unless they're like totally caked with the stuff, and you load your magazines and leave them for extended periods, I doubt you have a problem.

 

[Alan Fud]

I took the mags apart and used Q-tips but I don't think that I got all of it out as I had trouble reaching the middle of the mags. How about taking the mags apart and soaking them in gasoline?

 

[stickhauler]

Uh, gasoline isn't a real good choice for anything other than fueling an engine, it's not exactly the safest cleaning solvent. Do so if you want, I'd advise using mineral spirits, as the fumes off mineral spirits aren't explosive like gasoline is.

If you feel comfortable using it, your choice, I'd say no. My son swears by using "white" gas (Coleman's Fuel) for cleaning greasy parts. Again, not my choice for a cleaning solvent.

WardenWolf's method should work as well, my thinking is that using a solvent will break down the cosmo enough that you should be able to get every bit of it out, including any trace along the inner wall of the mag.

 

[Oro]

I just broke down a dozen 30-year old GI magazines. I found dried cosmoline residue gumming up the insides on a few of them. Not because cosmoline itself is bad, but mixed with powder residue it oxidizes and dries out. Cosmoline is good for storage but not practical in use.

1) What types of magazines?

2) Knowing that, we can tell you how to detail strip them, then it's easy to clean the springs and interior of the mag body. BreakFree works great for this (the aerosol type). Kroil, etc. - there are many good solvating chemicals to use for this.

 

[44lover]

The absolute best thing I have found to quickly and efficiently remove cosmoline from a magazine and a rifle for that matter is to strip everything down and blast it with Brake Cleaner. The stuff used to clean automotive brakes. It is basically the same as Gun Scrubber, it's just a whole lot cheaper.

 

[loadedround]

Many of you forgot the old army way of removing cosmoline. Placing disassembled rifles in boiling water for about 20 minutes, drying throughly and lubricating. You can do this at home in an old pot(and I do mean old) and boiling the mags until clean, assuming they are all metal. You may want to save that brake cleaner for the pot if you ever plan on using it again.

 

[DMK]

I haven't had the best luck with brake parts cleaner because it is so cold. Cosmoline is easiest to dissolve and remove when you can warm it and it melts. It can be like wax when cold.

Soaking parts in mineral spirits for a few days will dissolve the cosmo. As will Hoppe's #9. Mineral spirits is much cheaper. Either way, you'll need to scrub it a bit with an old toothbrush.

Soaking in a pot of boiling water will melt the cosmo and it will rise to the top of the pot (grease/oil being lighter than water). You'll still need to scrub the stubborn spots a little.

My favorite technique is a combination of boiling water, removing the items and scrubbing with mineral spirits while still warm.

 

[Alan Fud]

Hey, DMK. We both joined on exactly the same day If I boil it, how do I make sure that the inside is dry when I'm done and will not rust? Same for the spring? Just dry iy with a cloth? Can't dry the inside with a cloth because I can't even get in there or see an drops of water.

1) What types of magazines?

Sig Sauer P239 in .357Sig caliber

2) Knowing that, we can tell you how to detail strip them, then it's easy to clean the springs and interior of the mag body. BreakFree works great for this (the aerosol type). Kroil, etc. - there are many good solvating chemicals to use for this.

I know how to take them apart. I just don't know how to get the cosmoline out of the inside of the mags. Or, off the spring. I used a dry cloth on the springs but they still feel a bit sticky.


Thanks in advance.

 

[Manco]

I've seen claims that oil will harm ammo, but have never seen or heard any absolute proof of that claim. I'd say it's bogus, most modern ammo (well, factory ammo anyway) would have the primers sealed in some manner. Cosmoline is only an oil based preservative, kind of like a runny grease compound.

Not all ammo (even factory-loaded) is guaranteed to have sealed primers, and ammo that is not sealed can eventually be compromised by any number of environmental contaminants, the most harmful of which would be penetrating oils/solvents and water (even from the air, over a long period of time, potentially causing hang-fires). Honestly, Cosmoline is highly likely to do anything even to unsealed ammo, which will be degraded faster by water in the air, and even then over a period of years or decades. That said, the fact that it theoretically could is enough to disturb some people, and I don't see a good reason to suggest leaving Cosmoline in magazines. Even if corrosion resistance is important, I'd be more concerned about the Cosmoline migrating on a hot day and potentially gumming up the magazine in the process. The bottom line is that it is best, in my opinion, to remove the stuff even though it should not harm ammo in any practical manner.

 

[rocky branch]

The only old army way I ever saw was split barrels of solvent and brushes.

Cosmoline is only for long period storage. All of it should be removed.
Friend of mine worked in a training camp during WW2.
One job he had was to degrease new carbines.
They dumped all the metal into gasoline.
Not great stuff to handle, but we used it on the farm and it cuts grease like crazy.
Used to mix in some kerosine sometimes.

 

[Oro]

I know how to take them apart. I just don't know how to get the cosmoline out of the inside of the mags. Or, off the spring. I used a dry cloth on the springs but they still feel a bit sticky.

Use one of those solvents (or similar) mentioned above. Scrub out the inside with a bottle brush if you have one or an old toothbrush. It will remove easily. Same for the springs.

Very, very lightly oil the spring and tube inside and reassemble. You don't want it with lots of oil inside the body - it will serve to collect more powder residue and develop crud again. Too little oil in there is better than too much.

 

[W.E.G.]

WD-40 is lousy for most gun maintenance, but it sure does melt cosmoline.

Even better if you warm it.

Ziplock bag with the part, and a generous dose of WD-40, left to sit in the sun on a warm day, should clean up nicely with a toothbrush and paper towels.

Then you can use the paper towels to wipe the oil-leak crud off your motors.
WD-40 is really good for that too.

 

[WardenWolf]

Well, the method I mentioned above has always worked well for me. I've used it on everything from PSL magazines to Makarov magazines. Gets them nice and clean in short order. It's not as thorough as some of the above methods, but it does exactly what you need with a minimum of effort and mess. A lot of the above methods are really overkill. What little residue that's left after my method won't hurt anything, and may even lubricate the mag a little bit.

 

[Shadow 7D]

Hot water bath, just get a bucket of boiling water, or just hot water, and drop it in, wait a few and shake it out, most of the cosmo is gone and what's left can be easily cleaned by wiping it off, no solvent, no huge mess.

 

[Ala Dan]

Hey Alan My Friend-

Only us old farts still use the term "Cosmoline"

 

[fireman 9731]

Another vote for boiling water.

When you pull the parts out hot, the water evaporates right off and dries very quickly. Just lubricate lightly and then you are good to go.