We love our milsurp (military surplus) ammunition for our AK’s, but some of them are “corrosive” and require special cleaning after a range day.
It isn’t if you follow our guide that covers why some ammo is corrosive and how to quickly clean it so your gun doesn’t rust.
Table of Contents
So what makes some ammo corrosive? It depends on the primers and whether or not they leave behind salts when fired.
These salts attract water from the air and we all know what happens with water and metal and salt.
For the chemistry guys out there, the primers leave behind potassium chloride or sodium chloride (common table salt) when burned.
There’s two types of centerfire primers—Boxer and Berdan. Not sure what centerfire or primers are? Check out our Basic Bullet Guide.
Boxer primers are not corrosive while some Berdan primers are. It’s better to play it safe and just think of all Berdan primed ammo as corrosive.
Almost all corrosive ammo is older military surplus ammo.
So why do we bother with this old stuff that rusts your gun?
Simple fact is that they shoot great and are CHEAP.
Our favorite ammo for our AK’s is the Yugo M67 which is only mildly corrosive and also non-magnetic. They go for less than 20 cents a round while others such as PMC or Sellier & Bellot go for 50-70 cents each.
That adds up!
But…they are getting rarer to find, so make sure to stock up when you can.
How to Clean Corrosive Ammo
We’ll be using an AK pistol for illustration purposes, but this overall method can be used for anything shooting corrosive ammunition.
We talked about salts above and here’s a scary photo of what could happen if you shoot a lot of corrosive ammo and just leave your gun alone. We recommend cleaning it the day that you shoot, although in drier climates we’ve gone 24 hours with no signs of rust.
There’s tons of methods out there, but to get rid of salts, you need to flush it out with hot water.
That’s all there is to it.
Some other recommendations say to use soapy water, ammonia, or other water based cleaners, but it just boils down to water taking away those salts.
We field strip our AK and put it under the tap with really hot water and just let it sit for a few seconds. We like it as hot as possible since it will dry off much quicker. If your sink can’t fit a gun or can’t get as hot, just boil some water and run it through.
Make sure the water not only goes through the barrel but also the gas tube where most of the salts will settle.
We also run the spring, bolt, and piston through the water.
Afterwards, just let the water dry and clean as usual!
Run out of things to clean? Check out our Best AKs article to get some more toys.
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Hey thanks! :D
Here is how I clean corrosive ammo. Suggestions for improving the process appreciated. I completely agree that water is the key ingredient for removing the corrosive salts.
I use Ballistol mixed ten parts water to one part Ballistol. Once mixed, the solution looks like milk. If the solution sits for an extended period, it can separate. Shake the mixture thoroughly before use. The water in the Ballistol mix cleans the corrosive salts, while the Ballistol leaves a protective finish once the water evaporates. I put the Ballistol mix in a spray bottle for convenience.
When finished shooting I remove the bolt and any other parts exposed to firing residue and spray them with Break-Free CLP aerosol. I do not expose the weapon to any moisture. I spray CLP down the bore until it comes out the muzzle. I spray into the locking lugs, chamber, and any other areas exposed to firing residue. The CLP breaks down the residue and makes cleaning easier once I get home.
At home, I scrub the affected parts with a nylon brush to loosen any firing residue and wipe dry with a clean shop rag. Next, I spray the Ballistol mix down the bore until it runs out the muzzle. I also spray the bolt, bolt carrier, springs, inside the gas system, and on the fire control parts. The grime drips off as I spray the parts. I keep spraying and using nylon brushes until the runoff is clean and appears the same color as the Ballistol mix.
Once the runoff is clean, I push a dry patch through the barrel. I remove any muzzle device and clean the threads and muzzle device thoroughly. The corrosive residue can build up in the expansion chamber and on the muzzle, causing heavy corrosion. I spray more Ballistol mix down the bore and run more patches through the bore just to be sure it is clean of all corrosive salts. When finished, the Ballistol mix leaves a protective barrier.
Finally, I clean the bore with regular solvent to remove carbon and copper. Then I spray the bore one last time with the Ballistol mix to be certain all corrosive salts are gone. Corrosive salts can get under the copper fouling and cause corrosion if they are not removed. As a last step, I lightly oil the barrel and other parts with a patch coated in Break-Free CLP for storage. For long-term storage, I wipe down the parts with Eezox.
One issue never mentioned is how to deal with wood furniture during the cleaning process. Lots of surplus and Combloc rifles have wood furniture. Sometimes the wood furniture is difficult to remove before hosing down the rifle with water -- so difficult, in fact, that it causes me not to want to shoot the rifle, a Bad Thing. Robski over at AK Operators Union has a video titled "Corrosive Ammo" in which he simply hoses down a brand-new PSL (with wood furniture) using a water hose after shooting corrosive ammo. My concern is that the wood retains water, swells and shrinks as it dries, cracks the wood, and retains moisture in hidden spots causing the metal to rust. The only preventive steps I have seen for this problem are (1) cleaning with a mix of Ballistol and water, and (2) using compressed air to dry the rifle thoroughly after cleaning. I do not believe these steps are completely effective, but they are the best I've seen. I also think varnished wood would be more susceptible to this problem than wood treated with boiled linseed oil.
The title of your article was "How to clean corrosive ammunition" You're whole article was aimed at firearm cleaning and not one word was mentioned about cleaning ammunition.
Why would you want to clean ammunition? I can understand cleaning used brass if you are reloading, but why clean "dirty" ammunition except maybe wipe if off with a rag? I think you should get some Brasso, polish all your dirty ammunition, and see how that works for you.
Bull, I think you missed his point.
Correction, no such thing as "mildly corrosive" it either is or it isn't corrosive. I have a LOT of METAK 7.62x39 and I flush with hot soapy water each day when firing.
From a croatian shooter. Well most of the surplus ammo is corrosive, but there definitely is "mildly corrosive" and "horrendously corrosive". Example for the first one is as noted M67, which I left one time for about 12 hours without touching the rifle, there was actually no surface rust at all. Meanwhile, my friend got his hands on some of the Norinco ammo, and on my Yugo M59/66 it rusted in the matter of 5-6 hours! Gas tube was orange, and to this day I can't seem to get all of it out of the chamber (it has patina now). Bore already had little orange spots, the valve was orange was well. I have never seen something like that in my life (still have photos). When we realised that, he immediately sold that crap. Exclusively S&B or M67 now.
Change the title. Nowhere does it tell you how to clean corrosive ammo. It’s about cleaning your gun after using corrosive ammo!
I have a Mosin-Nagant that I shoot occasionally, can't get that thing in the sink not to mention the wood stock. What would be best for cleaning it?
I soak a cotton patch in water to clean my mauser, It seems to work just as nicely. I also recommend putting a patch soaked in CLP through it after words to keep it from rusting.
I always thought AK's were designed to shoot this kind of ammunition with no issues...
No gun is going to run any ammo without any issues, but anything you're shooting corrosive ammo through is going to need to be cleaned a specific way to function reliably. Even the legendarily robust AK will fail if not maintained properly, and with special consideration for corrosive ammo.
You always need to clean your rifle or pistol after shooting. AK ammo has a lot of this kind of ammo and it's cheap to shoot just like the steel cased ammo for AR but you Still need to clean you weapon afterwards. I am bad about it myself. Use COMMON SENSE.
Short, sweet & to the point, very good article.