Corrosive ammo question


I know that one is supposed to wash the barrel with warm soapy water after shooting corrosives. I shoot a M38 Mosin-Nagant and a post war Turkish Mauser with relative frequency using definite corrosives, Chinese early 50’s and Turkish war time ammo. Being busy and disorganized, I never clean them immediately. It may be weeks before I get to cleaning. I do store them in a well air-conditioned environment. Visually I see no classic pitting, the barrels look like made yesterday. Am I protecting them by denying mosture to the salts in the barrel or I just don’t see the effect visually?


Probably chromed barrels. WAG. Very helpful in that regard. Offering a less porous surface for the salts to react with.


Vlad: Your rifles don’t have chrome-lined bores, you’ve just been lucky so far, aided, probably, by indoor controlled humidity. Sometimes ambient humidity can be low for fairly extended periods, at least in some places. If you don’t clean them prompty shortly after shooting you’ll get bitten sooner or later. Jack



Nice seeing you at the show and meeting your kids. Nice young people.

Jack is right on about your rifles. Neither of the those types would have chromed bores. Corrosive ammo, in the middle of summer day time in the Sahara desert will not hurt a gun barrel. The primer residue is not what corrodes and rusts the barrel. The residue draws moisture out of the air to it. It is the moisture that rusts the barrel, I suppose aided by the residue. I have very occasionally found tiny rust spots, thankfully that come out easy with no pitting, in barrels after firing non-corrosive ammo. I suppose any dirt or residue in the barrel can become saturated in this wet San Francisco Climate. S.F. of course, for the few that might not know, is a peninsula surrounded on three sides by salt water. In the rainy season, which can be anytime of the year, the air is saturated with water - you can constantly feel the dampness even when it isn’t actually raining. While I believe non-corrosive priming residue doesn’t actually attract moisture to it, like corrosive priming “salts” do. if there is enough moisture in the air it can collect in the residue in a very dirty bore and act somewhat like corrosive ammo.

I always try to clean my barrels within a few days of firing even though I don’t use any corrosive primed ammo ever - not worth it to me. If I can’t get non-corrosive ammo, I load my own. For those with the time and energy to clean the barrel right away after firing, and for a few days until the pores no longer sweat out more residue (three successive days of cleaning using takes care of it - less if only a few shots have been fired), there is nothing wrong with firing corrosive stuff and no damage need ever occur to the barrel.


John: How does the barrel absorb the corrosive salts? and then what causes them to "sweat"out? Vic



I don’t think it is the barrel that absorbs the moisture. It is the residue of the primer that absorbs it, and then you have these “wet” spots sitting in your barrel. I am a dunce in chemistry, so cannot explain the whole process, because I don’t know it. I had this whole process explained once to me by my friend who was the U.S.Customs Chemist in San Francisco. I thought that it was the primer “stuff” itself that rusted the barrel until then. As far as “sweating out” I don’t know that process either. In fact, I just used the slang. I know that you can clean a barrel fired with a lot of corrosive ammo until it is bright, shiney and clean, and the next day it will look black like the inside of a coal mine again. It must be cleaned again, and so on. In the Army, we were required, no matter how our bores looked, to clean them every day for three days. All our .30 Model of 1906 ammo was corrosive, at that time. I have had the same thing happen with my own guns after a heavy firing (several hundred rounds) of non-corrosive, but a second cleaning usually finishes the job.

Wish I was more scientific, but the hard sciences were never my storng point, to say the least.
I have actually learned more science in the last 20 years than I ever knew even after graduating from a couple of years at college. I flunked chemistry in High School, the only course in my life I ever got less than a final “B” in. Of course, I missed two weeks of the course with some high school-age illness. Wasn’t measles - forget what it was. That set me in a position where I just couldn’t keep up with the class, which I was already struggling towards a C- or something.

Sorry. Maybe someone on the site who, unlike me, has a brain in his head can really explain the technical aspects of how these primers work, in the language of chemistry. For me, might as well be Chinese!

John Moss


Dear All those concerned about “Corrosive” primers, here is a review of my High School Chemistry (back in the 60s, when education was still a serious matter).

Corrosive Potassium Chlorate Primers, when they ignite, produce Potassium Chloride amongst other things. KCl is a salt ( like Sodium Chloride, common table salt), and it also has the property of Deliquescence ( absorbing Moisture (H2O) from the atmosphere). This causes the small “droplets” of Water Plus Chloride in contact with the steel. Then the Acid Oxidation of the steel takes Place…some Water Chemically Binds with the KCl, producing Ions of Chlorine, Hydrogen, Hydroxide and Potassium…the electrochemical reaction , in contact with the Iron (Fe) in the steel, causes the formation of Ferrous and Ferric Oxide (“Rust”), as well as Ferric Chloride…following the rules of Chemistry that say that compounds tend to form which are stable… and Iron Compounds are more stable than Potassium compounds; Thus the oxidation of the Iron in the Steel progresses, as long as there is Water and Potassium Chloride ( Water and Air provides the “Oxygen” and the Potassium Chloride
produces the Acidic environment when combined with Water which changes the pH of the Reaction, favouring the Oxydation process.

The Whole reaction is complicated by the Primer residue Mixture, which contains other more labile Oxides and Salts, to fuel the reaction.

It would probably take a College major in Chemistry to explain the whole Electrochemical and Physicochemichal reation processes, but there you have it in a nutshell. Corrosive Primer Residues Plus Moisture Plus Air Plus Gun Barrel=== Rust.

Solutions to the problem:

  1. Use Noncorrosive primers
  2. When using Corrosive primers, or those of Uncertain composition, Wash barrel out with Warm or Boiling water, with or without ammonia (which only cuts away copper fouling) and with or without a soapy detergent ( which cleans away all the particulate fouling of any description, and allows the water to penetrate ( reduces surface tension) right to the metal.).

Then dry well ( remember, even clean water can still rust a barrel, albeit more slowly).

  1. If stuck for time,and Warm water, use GI Bore Cleaner ( WW II Type) or similar product, which has a Water-lanolin Base, to temporarily cut down the oxidation effect, then clean properly at second sitting.

Good Luck and Good shooting.

Doc AV
AV Ballistics Shooting Corrosive Ammo since 1963…and still doing so.



Are you saying that salt and water cause rust?? Do what we did in the Navy. Paint it!!

That was a great explanation. Even I understood it.

You mentioned ammonia. Be careful of ammonia. It will also rust a Chrome-Moly barrel. Always flush it out with water or, preferably, a solvent. It doesn’t seem to hurt stainless barrels but it’s not a good idea to leave it in them either.




Ray have found brown paint does the best job it camouflages the rust. During boot camp the month at rifle training we had to clean our rifles with bore cleaner every day after shooting and with hot water at least once a week. Inspection was held every day after cleaning. In combat when ever you had time and when cleaning supplys were avaliable, which were short sometimes. Never saw many rusted bores in Korea. Maybe the 40 degree below zero temperature had something to do with it.
What kind of grease did you swab jocks really use to preserve bores with? Have often wondered how long it took to prepare a sub deck gun to fire after surfacing.



KCl dissolves in water, especially warm one, very easily and quickly. So just running a lot of warm water will stop corrosion.


Going full circle and comimg back to your original post. Why are you using such rubbish ammunition? It can’t be accurate and there seems little point in using it if you can’t be sure of it. It must be going all over the place. War time Turkish ammo is getting on for seventy years old now and was probably rubbish even when it was new.

Don’t you have any source for Privi Partisan ammo or similar ?

My friend Ron often used to say “Cheap ammunition is the most expensive ammunition you can buy” Save ten cents on ammunition and risk ruining a couple of good old rifles.


Sorry, Vince, you are correct, but I am not concerned with precision. If I were, I would buy a modern gun with modern ammo. What I am about to say is anathema at this forum. I shoot old guns using only iron sights with old ammo employing my old eyes with no eye protection. This is my own cheap reenactment of past wars. I blow up a baloon about the size of human head. If I hit it at about 200 feet, I am happy. It takes me 2-4 rounds to take an evil baloon down. If I miss, I still wake everybody up in a half a mile radius, so I am happy again. And I make collectable wasted ammo in the process.


Vince, that Turk 7,9 is not as bad as you think. My nephew and I have used a fair amount of it in his K98k and it performs well. A few years are known for split necks, but otherwise it is decent surplus ammunition. For shooting at steel “gongs”, inexpensive surplus is A-OK.



If I remember well:

KCL + H2O = H+ + CL- + K+ + OH-

Then there will be a REDOX reaction between the HCL acid + water and the Iron ions


I have heard that spraying a little 50/50 mix of water & Windex cleaner (has ammonia in it) down the bore after shooting corrosive ammo will help clean out the gunk before it has a chance to set in, which I was told takes only hours. After spraying the water/Windex mix down the barrel you have spare time to eventually get home and clean the barrel with proper cleaner and oil.


Vlad: Using any firearm, even the little .22 rimfire, without eye protection is a very bad idea. Jack


In theory spraying some water mixed with a basic compound ( like ammonia or NAOH) should neutralize the acid compound.
It is an acid - base reaction that , anyway , will leave the resulting salt



In all my years of shooting what most people regard as bargain basement rifles but what we call “classics” I have always been at a loss to understand why people have sought out and bought such low grade ammunition.

to me the two are not mutually compatable. the price difference is not all that significant and If I am to spend a day on the ranges I want to see what a rifle is capable of achieving and not just burning up old military reject ammunition that was old before I was born and I am 56. Most of the old .303 ammo that comes on offer from time to time is so poor it isn’t worth buying. It has been cooking for decades in sheds in Pakistan or India since the 50s and is now utterly useless.

The Privi Partisan ammo now available has revolutionised the classic rifle scene in this country and many old Mostin Nagents, MAS 7.5s, 7.92mm and .303s have found a new lease of life with the new ammo.

And all for about 75 cents a round. The cost is not that great. I don’t know what it costs in the US


We are a number of owner and shooters of the cute little US Carbine M1 in our club, but getting anything on paper is difficult for most of us. They mostly use old SOE-delivered WCC, PC, WRA, LC etc ammo that both splits the case mouth and soots all the way down the side…
Prvi doesn’t soot, it doesn’t split its cases and it hits beautifully.


Wow. I would quit shooting at .75 per round. I can see where your bias against surplus comes from with your Pakistani experience. The vast majority of surplus on the US market is very good ammunition, but anything from India and Pakistan is automatically suspect. The Turk 7,9 originally sold for about .07 per round, on chargers and in bandoleers. It is not match grade ammunition, but it is not supposed to be or advertised as such. For “paper punchers” looking for the smallest groups possible, handloading is the only way to go. My Mosin-Nagant rifle with an “experienced” bore will shoot 2-3" groups at 100 yards with it’s favorite brand of com-bloc surplus ammunition. It killed me to do it, but I bought some Prvi 7.62x54r ammunition, mostly for the boxer primed brass. Loaded ammunition was .60 each, primed brass (Winchester made by S&B) was .50 each. I’ve been shooting berdan, steel cased surplus for $.15 each… But, I needed some reloadable brass to see what the real accuracy potential of my rifle is.

No one seeks out “low grade” ammunition, but we all want “low cost” ammunition. The two are not always the same. I can pay 1.00 per round for factory .223 Rem. match ammunition for competitions or I can handload it for .30 per round. Same goes for .30-06 for my M-1 Garand rifle. I can practice with 40 year old surplus (surprisingly accurate) that I bought for $.38 per round and compete with more accurate handloads for a few pennies more.