Scott's Gunsmithing Service
Scott's Gunsmithing Service

The HORRORS of Corrosive Ammunition

Corrosive Ammunition Cleaning Tips

As a Gunsmith I often see Firearms that have been ruined by Owners who haven’t been taught the proper way to clean their Firearm after firing them with Corrosive Ammunition.

Some Surplus/Imported Ammunition made from the 1940’s up until the 1990’s used Primers with Mercuric Salts in the Priming Compound in the Primers. When the Primer is fired, Corrosive Salts are deposited all inside the Barrel of the Weapon and anywhere Powder, Carbon, Copper Residue travels.

Fulminate of Mercury was discontinued by all major ammunition makers for use in Small Arms Primers by the late 1920's due to Corrosion of the Brass and failure rates that increased as the Primers aged. The Corrosive Salts used in Ammunition Production from the 1930's through 1990's was Potassium Chlorate which is also the same salt left by Pyrodex. That is the Salt that will cause Corrosion in your Firearm.
Some often comment; “Why shoot Corrosive Ammunition?" Simple answer is that it is often very cheap Ammunition compared to most current Production Ammunition, and other than the Corrosive Residue issue, the Ammunition shoots fine BUT, it is not Ammunition for the "lazy" Shooter.

If these Corrosive Salts are not removed they will grab moisture or humidity from the environment
and corrode the inside of the Barrel, Bolt and other areas of the Firearm. Even Chrome Lined Barrels can corrode, so don’t neglect cleaning Corrosive Ammunition residue just because the Bore or Chamber is Chrome Lined. If Corrosive Ammunition is being used in a Semi Auto Firearm the damage can be even more extensive because the Corrosive Salts get inside of the Gas System and back into
the Action as well, so don’t neglect these areas when you clean.

Just swabbing a Barrel with Oil WILL NOT stop the Corrosion Process, it will just Rust and Corrode under the Copper and Carbon Deposits, right under the Oil. Using Oil based Solvents and Oils will not get the Corrosive Salts out contrary to what some Gun Products advertise. Some Gun Solvents and Cleaners state that the Product will neutralize the Corrosive Elements. DO NOT trust the label or
the claims. I have seen too many Firearms ruined by people using said Products and improper Cleaning Methods when dealing with Corrosive Residue.

The only answer is to remove the Corrosive Salts. This is easily done by using a Water-Based Solvents, or just plain Water.

How I Clean Corrosive Firing Residue:

I use and HIGHLY recommend a product called Ballistol. This Product is not utilized straight for this specific purpose, you make a mix with it 10 Parts Water/1 Part Ballistol. Once mixed, the Solution
will look like Milk. If the Solution sits for an extended period of time, it can separate, so before usage shake the Mixture thoroughly.

The Ballistol Mixture cleans the Corrosive Salts with the Water and leaves a nice protective finish of Ballistol Oil once the Water evaporates. I take my Ballistol Solution and put it in a spray bottle which makes using the mixture very convenient. Ballsitol is a decent cleaner too, sort of an “Old School” CLP.

Alternatives to Ballistol & Water Mix:

If you are cheap you can use Windex to flush Corrosive Salts from a Firearm. Windex has high amounts of Water and Ammonia. The Water in Windex helps flush out the Corrosive Salts, and the Ammonia helps the Water evaporate. Many feel that this is not necessary since the Water is
what is doing the work. Be careful though, Windex leaves NO protective properties once it evaporates. Windex does NOT work better than Water Alone.

If you are super cheap then just Water works ok, Hot Water works slightly better. If you use HOT Water please take precautions to avoid burns. Hot Water with Soap works a best of the 3 Water Options. You must be sure the Barrel and other Parts are dried and then Oiled to prevent
My Corrosive Ammunition Cleaning Tips:
When you are finished shooting for the day, remove the Bolt and any other Parts that get exposed to firing residue and spray with G96 CLP Aerosol or Breakfree CLP Aerosol.

DO NOT EXPOSE THE WEAPON TO ANY MOISTURE, Just use the CLP Aerosol and spray the exposed areas down.

Spray enough CLP down the Barrel until it comes out the muzzle. Try to spray into the Locking Lugs and Chamber as well and any areas exposed to Firing Residue. The CLP will break down Firing Residue to make cleaning easier once you are Home.

Once you get Home, scrub the effected Parts with a nylon brush to break free any firing residue and wipe the dry with a clean Shop Rag, old clean T-Shirt, or Paper Towels. Next, I spray the Ballistol Mixture down the Barrel, on the Bolt Body/Carrier, on the springs, inside of the Gas System, and on the Fire Control Parts. The grime will run off as you spray the parts down, so do this over an Oil Pan, Sink, or outside the House. Spray Enough Ballistol/Water Mixture down the Barrel until it comes out the Muzzle. Try to spray into the Locking Lugs and Chamber as well. Keep spraying and using
nylon brushes till the runoff is clean/white.


Once the runoff is clean, then push a dry patch through the barrel. If you have a Muzzle Device REMOVE it and clean the threads, and Muzzle Device thoroughly. If you have a Muzzle Brake then its VERY important to remove it as the corrosive residue will build up in the Expansion Chamber and on the Muzzle and CORRODE Heavily.
Once the runoff is clean, then push a dry patch through the barrel.

Spray some more Ballistol/Water Mixture down the Barrel and run some more Patches through the Barrel just to be sure it’s CLEAN of ALL CORROSIVE SALTS. When you are satisfied everything is
flushed, you don’t have to run a final Dry Patch, the Ballistol/Water Mixture leaves an Oil Protection Barrier. I then move to cleaning the bore to remove Carbon and Copper. I use a product Called Wipe Out Bore Foam. It’s a Cleaner that requires NO BRUSHES, just a Patch and Jag.
Wipe Out Bore Foam or Wipe Out Tactical Advantage

You simply won’t find a better Bore Cleaner that works so effectively or is as safe for your bore as WipeOut Bore Foam.

I scrub the bore from the breach going in one direction with a Patch and Jag until the patches come out clean. The Wipe Out will break away some Copper and Carbon Fouling that the Ballistol/Water Mixture simply couldn’t get to. I suggest you make one more spray down the Bore with your Ballistol/Water Mixture to be sure all signs of Corrosive Salts are gone. I do this because Corrosive Salts can get under the Copper Fouling and cause corrosion if they are not removed. Just be
sure to get the Copper Fouling OUT and then use one more use of Ballistol/Water Mix.

I, then lightly oil the barrel with patch coated in Breakfree CLP, Weaponshield CLP, or G96 CLP for storage in the safe.

Sounds like a lot of trouble?

Well, if you let your Firearm rust you cant put the metal back, there is no way to restore it to "perfect" unless you want to start replacing Barrels, Bolts and such. With little effort, you will always have a "like new" Firearm. I have tried pretty much everything on the market ands the methods and products listed are the most effective and cost efficient way to approach this subject.
Basically, if you choose to shoot Corrosive Ammunition then you must be willing to immediately clean your Weapon after coming home from the Range.

So there is my advice. Take care of your Firearm, and when you need it your Firearm will take care of you



Common F.A.Q.'s:





Does anyone use this stuff on Firearms that don't shoot Corrosive Ammo? Reading around, I got the impression that people use this on just about anything relating to firearms



I use it on all of my guns after cleaning if I don’t have access for an Air Compressor.

I don’t use it as a stand-alone CLP or Lubricant as I prefer Synthetic Motor Oil and Synthetic Wheel Bearing Grease for my Lubrication needs.

Follow this link to see how I clean my firearms: LINK
I'm trying to figure out just what Ballistol product you use. Some is called sporting oil, some is spray, some comes by the gallon. Exactly what Ballistol do you use and what size? Also, do you buy the spray cans? Any and all help appreciated
I get this size:Ballistol 16 Ouncs Sportsman's Oil

Fill 2, 1 gallon milk jugs about 3/4 full of water, then take the can of Ballistol and put half of the Ballistol in each. It will turn into a milky color. Use these for your reserves. Fill a spray bottle with the mix and apply to your guns. If the solution separates from sitting just shake it up before use.
After the above, do you still follow-up with Wipe out, or is using Ballistol stand-alone enough?
Yes, I still use Wipe Out Bore Foam. The Ballistol only removes the surface Corrosive Salts. It does not
remove Copper Fouling, or Carbon Fouling, but the Wipe Out does. If you don’t de-copper the Bore, then Corrosive Residue can sit underneath the Copper Deposits and still cause Corrosion. After the Wipe Out Treatments, I spray the Bore with my Ballistol Mix one more time for a precaution to ensure I have removed ALL traces of Corrosive residue.
So what DID the Germans and Russians in the field use? The 2-part oil can that came with my Mosin? 1 part oil, the other Ballistol?
They had specific Solvents to take care of the Corrosive Salts. I have heard that if they had no Solvents that they used to urinate in the Bore. No joke. Supposedly, the Water and Ammonia in the Urine does a darn good job at flushing the Corrosive Salts out of the Firearm.
I have been told spraying the inside of the barrel and bolt down with WD-40 and running patches through it. Thoughts on effectiveness?
WD40 is generally the worst thing ever applied to a firearm. WD40 has made Gunsmith millions in Cleaning Jobs for the past 50 years, when, I repeat, when applied improperly. Using WD40 in the bore ALONE is not terrible. The solvents in it will help clean the bore, and the Preservatives in the Solvent will help prevent corrosion till you get home.

The WD40 won’t get the corrosive salts out or get under the Copper and Fouling as good as Ballistol and Wipe Out regiment. WD40 does displace water quite effectively. If you use WD40 to flush out a waterfowl gun or one that was soaked in the rain, or took a spill into some pond then you’re ok, If, and ONLY, IF you blow the WD40 out. Realistically you will need an Air Compressor to blow out the WD40 properly. If you don’t have an air compressor, then step away from the WD40. If you don’t blow all of the WD40 out of the internals, it will dry into a hard waxy substance and gum up you gun internals.

In a pinch if you don’t have access to good Wipe Down Products like Eezox, it’s not a bad Protectant for wiping down guns by spraying it on a Rag and Wiping the Firearms EXTERIOR down.
I've always heard you should use something ammonia based because the ammonia helps "neutralize" the corrosive salts, but what you're saying is that they are hydrophilic and attract moisture. So the ammonia thing is an internet myth?
What about using sweets 7.62 to run down the barrel with a couple of patches. I figure there is enough ammonia in there to neutralize just about any acid and then follow it up with some CLP?
The ammonia in Windex is more like denatured alcohol than ammonia. It really only helps with
helping the product evaporate faster.

True ammonia based products are great for removing copper fouling but can be very harmful on the bore over time if used improperly. Sweets are one of those products to use caution with and because if the risk I do NOT use it. Wipe Out Bore Foam has the same cleaning power without the risk.

Ammonia does nothing to help neutralize or flush out the salts. Water and only water based products will assist with Corrosive Salts.
I’ve been using corrosive ammo in my 5.45x39mm AR for the past year and thought I was having good results with Windex and WD40. At the range I disassembled the bolt and soaked it in Windex or WD40 (heard this was ok to do). I then sprayed the WD40 down the barrel really good. I then ran some patches through it and took it right home. At home, I disassemble everything again, and sprayed everything down very good with Break Free Powder Blast. It really seemed to blast everything away, get things clean, and it dries fast. I then use a brush, patches, cleaners, and oils to perform the normal detailed cleaning.

After only a few months I was horrified to see corrosion in in my Gas System, Bolt Carrier, Bolt Head, Muzzle Device, and Barrel. Any recommendations for an AR that shoots corrosive ammo?
I don’t suggest introducing ANY water based products to a firearm till your HOME and ready to clean. Doing so can actually PROMOTE Corrosion. More than likely your corrosion occurred because you introduced moisture before you could reliably flush out the salts. The Windex was that moisture. It’s like throwing gas on a small fire. For AR's that shoot corrosive I suggest you use my Corrosive Cleaning Methods, then follow my Standard Cleaning Methods listed Here:
I bought Break Free CLP Aerosol. Can this be used on all types of finishes such as nickel, stainless, and bluing? How about on black rifles such as an AR15? Is there any metal I should not use it on? Replies appreciated. I bought Break Free because so many of you recommend it.
Breakfree is a good product. I use it on my firearms when I run out of Synthetic Motor Oil and Synthetic Wheel Bearing Grease. It does not help flush out of neutralize corrosive salts left behind
from corrosive ammunition. If you shoot corrosive ammo follow my instructions then follow with Breakfree CLP.
Should you avoid using anything with Aluminum, such as AR15 Lowers? I heard at one time or another some problems with galling if you use the wrong lubes and cleaners.
I don’t like or use any products with graphite in them, they will damage aluminum, and so will some generic cleaners such as simple green if used in a careless manner.

I do not recommend Frog Lube, Miltec, Tetra, or WD40 Products for Firearms!
How much liquid through the Barrel is enough to make sure there's nothing Corrosive left behind? After firing my Mauser I probably poured about 1 cup or so of hot soapy water down my Barrel. This was a new experience for me BTW, and then I let it drain for a few minutes, wiped down all the exposed metal and used CLP to clean and oil the rifle. Did I use too much or too little Water?

I think I'm going to try Windex next time and the same question applies. How much is enough?
I usually do what you did but use a spray bottle with Ballistol/Water mix. I then follow up Wipe Out Bore Foam, and then I repeat with the Water/Ballistol Mix. The next day I repeat to be sure
everything "Bad" is gone.


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