Corrosive Primers

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Corrosive Primer
Cleaning Tips
With Additional Information on Mercuric Primers and Erosive Powders

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I'm the husband of the owner of this website and I would be pleased to share with you some information that took me years to figure out for myself.

Shooting inexpensive military surplus ammunition is a great way to enjoy your old firearm. However, if you don't take immediate corrective action, you will certainly ruin your bore within a few hours after firing.

Most military surplus ammunition made before & during WWII is corrosively primed. However, there are exceptions. The worst stuff seems to be the old Eastern European ammunition; particularly in calibers 7.62x54R Russian, 7.62x39 Soviet, and 7.62x25 Tokarev. This ammunition is usually great shooting but the "Commies" were churning out ammunition with corrosive primers well into the 1990s. The only exception to this was that the Soviets used non-corrosive primers on most of their 7.62 Nagant ammunition from the 1970s onward. Even if someone tells you that it's "Clean, Surefire, and Non-Corrosive.", don't believe them! They may be correct about the ammunition being clean and surefire, but you can't afford to take their word on the corrosive aspect. The Soviet Union (and Eastern-block countries) used corrosive-primed ammunition long after the rest of the world stopped using these compounds. Basically, it was a cheap and reliable way to make primers.

Do not confuse the words "Corrosive" between "Erosive" and/or "Mercuric". A corrosive primer uses a compound that produces corrosive salts when fired. Erosive ammunition uses priming and propellant compounds that tend to foul the bore with excessive residue. Although this is not corrosive, these compounds tend to make the bore surfaces wear down a bit faster than non-erosive compounds. The Soviets (and their allies) are notorious for using cheap/erosive powders in their ammunition. Even today, the biggest complaint most shooters have with Wolf ammunition is that it's overly dirty (a.k.a.: erosive). However, unless you fire several thousand rounds through your gun, you'll probably never notice the difference. Mercuric primers use a mercury formula in their priming compound. If you ever find old ammunition made in the 1930s or before, you must suspect that the primers contain mercury (although most don't). In this special situation, the cases MUST NOT be reloaded because the mercury compounds become embedded within the brass-case walls which will lead to eventual failure. Mercuric primers are also corrosive primers so the below method of cleaning seems to work well.

Some modern commercial bore-cleaning solvents take the above into consideration. A few years ago, few companies produced formulas that would neutralize the corrosive salts in surplus ammunition primers. This lead to many unhappy gun owners who thought that the over-the-counter bore cleaning solvent would do the job. It didn't, and many old surplus rifles were absolutely ruined. Even today, it's difficult to find a commercial product that "guarantees" it will do the job. For the most part, the current manufacturers have simply added ammonia to their formula without advertising it. Sweet's 7.62mm Solvent says their product contains 5% ammonia so this is one product that should do the trick even though they don't guarantee it.

A few years ago, most folks were simply using soapy hot water to scrub their bore (and then finishing up with the usual solvent & oil). This works great if you're thorough. Then along came the fans of Windex with Ammonia D. This too works fine if you're thorough. The reality is that you've got to neutralize & clean the bore within a couple of hours (preferably within minutes if you really care about your gun). Some old timers will even urinate down the bore if they can't get to a bottle of ammonia within an hour or two.

     Cheer up! there's a simple & inexpensive way to clean your old rifle from these damaging corrosive salts:

          MATERIALS: Go down to WalMart* and buy 1). a simple empty spray bottle, 2). a bottle of household ammonia, 3). a bottle of liquid dish detergent, 4). clean/filtered water, and 5). a spray can of WD-40.

          FORMULA: Mix 4-parts clean/filtered water to 1-part household ammonia. Then add 2 Tablespoons of liquid dish detergent and pour this concoction in your spray bottle and shake it up. If you use too much ammonia; it will eventually remove the bluing on your gun...not enough ammonia and it won't neutralize the corrosive salts. A 3 : 1 or 4 : 1 Water : Ammonia mix seems to be the optimum formula for safety and effectiveness. The liquid dish detergent acts as a sticky/wetting agent (which gives the ammonia a little extra time to work) and also helps to dissolve the corrosive salts. The WD-40 will be used as an field-expedient step to keep your bore from rusting before you get home (so that you may clean it as you regularly would).

          HOW TO USE: It doesn't take much so always carry a little spray bottle of this formula with you. IMMEDIATELY after firing your firearm with suspect-corrosive primers, remove the bolt or cylinder and turn the gun so that the muzzle faces down. Spray the Ammonia/Water/Soap mixture into the chamber and directly down the barrel. If you're shooting a revolver, then you must also spray each cylinder. If you're using an automatic pistol, you'll need to field-strip the gun and spray everything down. About 3 or 4 ounces is all it takes. Now, spray the bolt face or any other internal parts that may have come in contact with the propellant gases. If you've had a ruptured cartridge (or a mild load that didn't completely seal the chamber) then you'll need to spray just about everything. Try your best not to let the ammonia/water/soap spray touch the outside (blued) surfaces...if it does, just wipe it off and spray a little WD-40 on it. Give all this a couple of minutes to dry out and then spray everything down with WD-40 (this keeps things from rusting until you can do a better cleaning job at home). When you get home, spray the chamber & bore and bolt face again with the mixture and then run a patch several times through the bore. After this, clean your gun as you regularly do with Xenophile Bore Cleaner and Break Free CLP but any good product will do). DO NOT use WD-40 to clean your gun at this point!!! While WD-40 does well in some applications, it will actually dry out the necessary oils from the gun surface and it also tends to migrate through cartridge cases and into the primer (where it kills the priming compound).

Read more about corrosive primers and gun care formulas by CLICKING HERE.