Just in case anyone has used corrosive ammo in their M1 or other rifles here is some further info that may be helpful.
(Copy/Pasted Text of various web posts0Post:
The scope of the corrosive ammo problem was best addressed by an American Rifleman article entitled "Is There Salt In Your Gun Barrel?" at page 36 October 1971. Excerpted is the following to make the point:
"...Various solvents were brought out as bore cleaning solvents. Their success was quite limited. They left the bore apparently clean, but usually it rusted later and required cleaning again, often several times. That is still the consequence of cleaning with only the usual "powder solvent" after firing ammunition of the corrosive type."
"...When the primer is fired, the oxygen of this compound is used, leaving potassium cloride...This is akin to table salt and sea salt, and like them will rust iron and steel in the presence of water. There is water in the air under most conditions, and the steel bore surface, covered with wet salt, rusts.....The potassium cloride can pull water through heavy coatings of grease, so oiling or greasing a fouled bore does not protect it."
"...Trials have shown that the rusting does not occur in very low atmospheric humidities. But the potassium cloride remains unaffected until the humidity rises again for rusting to start or restart. This has been known to happen after the lapse of years."
"...Water is the best solvent of potassium cloride. Soap or sal soda (soda ash, washing soda) in the water cuts the stickiness of the foulding and hot water heats the barrel and makes drying it easier. A bronze bore brush breaks up the fouling and makes the cleaning easier and more effective. Stick the gun muzzle into a container of hot soap suds and pump the bore full several times with a bronze brush on the cleaning rod. If the bore cannot be cleaned from the breech, lay the arm flat to avoid getting water into the breech mechanism, and clean the bore with wet brush and patches. Dry the bore, and oil or grease it for preservation."
"Government bore cleaner is required by rigorous test to clean bores effectively after corrosive ammunition firing."
"Some questions remain."
"Will water cleaning prevent all damage? In general, no. Military experience even in peacetime showed that continued firing of corrosive-primed ammunition results in slow roughening of the bore. It seems to have been imposible in practice to clean the bore soon enough and well enough after every firing. The result was a prolonged annoyance, continual attention being necessary and the rifle bores eventually becoming more or less pitted though mostly still serviceable. Some of these were ruined, and many in civilian use have been damaged. But most damage can be prevented."
"Will water cleaning remove metal "jacket" fouling? No....."
Corrosive Ammo Cleaning Methods Discussion
The first thing to understand is that nothing neutralizes a salt. It is the end product of chemical reactions.
The best idea is to assume that most military surplus ammo, 7.62x54mmR, 8x57mm, .303 British, 7.62x39mm is corrosive.
Most NON United States milsurp ammo through at least 1980 is corrosive around the world.
Except for non-corrosive (semi-commercial by Norinco) Chineese 7.62x39mmn beginning around 1990, most military 7.62x39mm is corrosive whenever made. Recently made Russian commercial is not corrosive but that is now so expensive it is gone from most markets.
NATO headspamped 7.62x51mm and 5.56mm is non corrosive.
Most .30 Carbine is non corrosive, but there are French and Chineese look a likes that are corrosive. The Chineese is headstamped LC52, but the boxes are identifiable. Do not use that garbage. The French is corrosive. The Chineese is Berdan primed and my rule is that Berdan primed is always corrosive unless recently made. Some shooters are insisting some of the Chineese LC52 is non corrosive because it has not rusted their Carbines. More power to them. The garbage don't go into mine.
The flushing concept:
Once the concept of flushing away potassium chlorate primer residue is understood for being exactly that, flushing out and wiping off, then some evaluation of methods that will prove useful can be done.
Keep in mind there is the KCL salt residue itself and the accompanying problems of powder fouling and of copper fouling. Both of the extra problems help trap the corrosive salts.
Point 1: The potassium salts created by the primers are the end product of chemical reactions. They are not broken down and are not neutralized. That is why salt goes to the sea and stays there. Salts can be dissolved but do not chemically change.
Point 2: Water or water containing products dissolve potassium salts. Next to nothing else does. The potassium salts are not "neutralized", but simply dissolved for flushing out of the bore or for wiping off of the metal outside.
Point 3: Most modern bore cleaners contain no water and do a poor job of preparing potassium salts for flushing out. Modern bore cleaners can help dissolve powder fouling that helps release the salts to flush out. A different but related idea.
Point 4. Something to dissolve the potassium salts and something to break up powder/copper fouling works well in tandem to get the steel cleaned thoroughly.
Point 5. The now clean bore still has to be protected with an oil to prevent rusting.
For beginners, the most important thing is that they do not rely on modern bore cleaners for corrosive ammo. What they need to keep in mind is that Hoppe's #9 now has no, none, zero, nada, neutralization of corrosive potassium chloride salt capability. Whatever argueable ability it might have had years ago when the bottles were labeled as helpful and stunk to high heaven, it currently has no help at all in the mild smelling kind.
The actual action of Hoppe's is to partially wash out stuff from the barrel and break up powder fouling. Flushing out is different than chemical neutralization. With potassium salts, you can dissolve it, but it does not change form. Hoppe's without water does not dissolve it. It just partially flushes it out. Relying on Hoppe's is relying on very little help. Once cleaned Hoppe's cleaned bores usually rust a few weeks or months later.
USGI bore cleaner will dissolve and flush out corrosive salts in any of its many flavors and colors of performance based mixtures. The fluids were performance spec based items rather than a specific formula. The USGI bore cleaners are water based, dissolve corrosive salts, have a mild metal jacket fouling remover, and leave a water soluable oil in the bore when the water content dries out. You can actually watch the white milky kind dry and turn to a clear oil.
The result is a temporary coating of water soluble oil on the bore that offers some protection until a better oil can be used. Depending on which USGI bore cleaner is used, there is some very mild copper removal. The white milky kind produces a green/blue residue as it sits in the bore overnight.
Water based cleaners (Windex and such) may flush out corrosive salts fairly well, but don't actually chemically neutralize them. Windex simply dissolves the potassium cloride salts in the bore.
The ammonia in the water based solutions like Windex helps break up powder fouling releasing the trapped salts for flushing out. The ammonia also attacks copper deposits which also releases potassium salts for flushing out.
The potassium salts created by the primers are the end product of chemical reactions. As the end product chemical reaction, ammonia doesn't actually undo the KCL bonds. This is why the oceans are full of salt. It is the last product of chemical reactions and flows away with water. Windex just helps flush it out of the bore and helps dissolve it off of outside metal parts.
Windex and the various similiar water based cleaners leave nothing in the bore to protect it. There is no oil component in them of any sort.
Boiling water down a barrel is a long tested method to get rid of almost all corrosive salts because it flushes the potassium salts out of the bore very effectively. That should be followed by regular cleaning with powder fouling removers and jacket metal fouling removers and bore preservatives. Water works, expecially boiling soapy water, but in truth it is a mess because it is not just the bore that needs cleaned.
Using boiling water, cleaning the bore is easy with a short hose or tubing on a funnel, but the other parts of the rifle needing cleaned are not so easy. The entire bolt and bolt way, the trigger guard where you touch, and the muzzle all need cleaned. And lets not forget the entire gas system of a Garand.
Boiling water followed by three days cleaning with USGI bore cleaner is effective. All places corrosive salt bearing gasses can reach should be cleaned with USGI bore cleaner (outside of barrel, bolt face, bolt locking lug recesses, breech areas, and so on.) This is one reason USGI bore cleaner is so useful. You can scrub it into all sorts of places and then wipe it off without harm as it leaves a water soluable oil on the metal as the water content in the bore cleaner dries off the metal.
Boiling water also works so well partially because it expands the cracks in the steel and releases the salts from down inside the metal. Then it washes them away. It is also hot and drys the bore of liquid water.
For a one product system with the least work, USGI bore cleaner will work fine by itself. There are several different formulas and they are all water soluble oil compounds that dissolve and clean away potassium salts by flushing them out the muzzle. The white milky ones and the ones that are clearish smelling like benzene both operate the same way. They dissolve potassium chloride salt to be carried out of the bore. They also leave an oil coating as the water content evaporates off the metal. they have a mild effect on jacket fouling.
Good looking cans should be selected and the rusty, dented, leaking cans should be avoided as unknowns. Check every lid seal before buying.
It would be nice if some manufacturer marketed a modern equivalent of USGI bore cleaner. It is still being manufactured for the services as some weapons are corrosive primed in larger calibers. (As of Feb. 2010, I would guess most of that has been fired up in two wars, at least most all of the old M2 .50 Cal.)
There is a Birchwood-Casey product for cleaning blackpowder firearms but I am aware of no information concerning what it does to corrosive primer residue.
Keep in mind that corrosive salts are sufficiently hydroscopic (the ability to attract water) that they can pull water from the air right through oils and greases in the bore. Water is what causes iron alloys to rust. The oxygen in the water reacts with the iron particles forming iron oxide better known as rust. Salt attracts water causes rust. Oil and grease are not rust preventives when applied over corrosive salts.
Clean from the breech to muzzle where possible based on the firearm design. This pushes the salts out of the muzzle and away from the action system. Thoroughly clean gas systems if you must shoot the stuff in gas guns.
