Silver Bear .223 corrosion

roscoe said:

Any reason I can't tumble the rounds?

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In a vibratory tumbler, no.
In a wet tumbler, yes.

I also see no harm in lubricating the case a small amount after the cleaning and do so myself. Sometimes there is a lubricious dust coating from the tumbler. Mine is only pure cob and I towel the case off after so they need a snifter of OneShot.

Not sure how many you have, but I would wipe them down with a light oil and shoot them.

I don't like to vibratory tumble loaded rounds, or wouldn't do it for very long, if I did.

About 10 years ago when Brown Bear, Silver Bear and Golden Bear ammo were all the rage for 7.62x39, I settled on Brown Bear. I still have a ton left. This was when there was little info about how each would fare to time and the elements. I'm glad I did!

Sorry to hear about the ammo, but as you pointed out, it seems to be only surface level.

A rag with a little penetrating oil will cure that. I've been known to spray a little in the mag on a gun that's being cranky.
Your mileage may vary.

The silver on Silver Bear is a zinc coating. If you keep it in the box in ideal conditions or sealed in an ammo can it will stay as new. Loose rounds laying around or in less than ideal environments will develop spots. The one you have there has the most oxidation I've seen.

Silver Bear 125gr Jacketed soft point is one of my favorite factory rounds in 7.62x39. I keep one round out in the open on my desk to keep track of how they oxidize. A small spot or two will develop over time. I just knock it off with some extra fine #0000 steel wool and it stays shiny for another few months.

The half case I have upstairs in a closet is just fine in the original box and plastic bag.

I wouldn't tumble what you have there. Better to use some 0000 or 000 steel wool.

Speaking of tumbling loaded ammo; I've heard that will break down the powder granules, at least with extruded (stick) powders if left in the tumbler too long. Although I have no idea how long that would be before it happens. If it happens it can alter the burning rate of the powder into something that was never intended for that application. I would go the 0000 steel wool route.

Drop in a vibrating tumbler with either cob or walnut and a cap of Nufinish car wax. Let it run for an hour or two. Polish that corrosion right off and leave a coat of wax to protect it. Will also give you an opportunity to look over the cleaned cases for any signs of case damage. There have been so many studies on this to fairly well be assured there is not risk to the ammo. Heck most all new ammo is tumbled by the manufacturers before packing.

About 12 or 13 years ago I bought 2000 rounds of water damaged Silver Bear 308 ammo from J&G sales.

They were blowing it out at 15 cents a round at the big Crossroads of The West Gunshow in Phoenix.

Most of it had the white scale on it just like the Op’s ammo does.

As I needed some, I’d dump it in my vibratory tumbler to clean it up and then shoot it.

It was decent ammo, shot about 2” groups out of my M1A and seeing how it was soft point ammo used to kill quite a few hogs.

I ended up shooting it all over the course of a year or so and upon reflection, at 15 cents a round, I should have bought both pallets they had for sale.

Couple of hogs killed with that old Silver Bear soft point ammo:

I've tumbled lots of old cruddy looking loaded cartridges in a dry vibratory tumbler. No problems. A few years back (on this forum I think) there was a test run, regarding the potential degradation of powder after tumbling in a vibratory tumbler. As I recall, there was no difference in shooting results.

Also - in the past, I've tumbled all kinds of things, including old inherited dies that had rust on them. I usually experimented with media, added polishing compound, etc. Works quite well in most cases.

I tumble my loaded rounds for about 30min to remove lube and apply a small coating of nufinish polish, as stated a capful is enough for 2 or 3 batches and I also ad a couple of caps of mineral spirits, cut a used dryer sheet into 1/4ths and that helps with dust and crud.

I would clean a few of those by hand just to see it the case has any damage. If no damage is visible I would dump them into the tumbler with some corncob media and some polish, like NuFinish, ect.

I've tumbled lots of loaded rounds with no problems.

roscoe said:

I have some old Silver Bear that I pulled out of the box and it had a fine coating of corrosion. Being the scientist, I ran it through my Saiga. But perhaps 'run' is optimistic. The casings started binding up in the chamber and I had to pull a few out with pliers before I stopped the experiment.

Any reason I can't tumble the rounds? Seems like a waste otherwise. Also, it has incentivized me to go through all my old ammo and doublecheck the conditions of it all. I will admit to being surprised at the oxidization - I guess I thought the casings were more resistant to corrosion.

One example:
View attachment 1116095

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Pull one bullet and make sure there is no corrosion on the inside of the case, or on the base of the bullet












If the gunpowder has deteriorated and is outgassing dinitrogen oxide and nitric acid gas out of the case neck, primer pocket in the box, those gases will collect around the cases and cause the type of external corrosion you see in the pictures. Internal corrosion is evidence of gunpowder deterioration and old deteriorated gunpowder has burn rate instability and has blown up firearms.

If there is no corrosion, just oil or grease the cases before you fire them. You don't need a lot of oil or grease, a wet patch will do. That will reduce friction between case and chamber and the cases should eject. It would be a total bother to have to polish each individual case to smooth the surface.

roscoe said:

I have some old Silver Bear that I pulled out of the box and it had a fine coating of corrosion. Being the scientist, I ran it through my Saiga. But perhaps 'run' is optimistic. The casings started binding up in the chamber and I had to pull a few out with pliers before I stopped the experiment.

Any reason I can't tumble the rounds? Seems like a waste otherwise. Also, it has incentivized me to go through all my old ammo and doublecheck the conditions of it all. I will admit to being surprised at the oxidization - I guess I thought the casings were more resistant to corrosion.

One example:
View attachment 1116095

Click to expand...

how did you pull out the empty with pliers?

I stock steel case rifle ammo in a variety of flavors and zinc coating will rust faster than poly or lacquer coated steel. Fingerprints seem to cut that time in half.
I still have some Silver Bear 5,45x39 socked away in an ammo can with dessicant. Stiil shiny after 10 years. But my last choice for long term storage. And cardboard attracts moisture, if it's in boxes, take em out or make sure it's always stored dry.

Load up poly coated 7.62x39 in a mag along side zinc coated and push out rounds by hand. That zinc pops out as easy as brass, that's it advantage to me. But brass case or brass 'washed' is a better choice for long term.

I think a light coating of oil is all you need. Maybe lay all your ammo out on a plastic sheet or trash bag and spray it all down with a good spray lube like Hornady One Shot or RemOil.