Tumbling Dirty or Corrosive Brass

[landtoy80]

I will be getting my tumbler this week and have a few questions.

Do I need to remove the primers first or doesn't it matter.

Some of the brass has some mud/clay on them, how should I go about dealing with that? I tried soapy water. most of the big chunks fell off but there was still a coating of dirt in them.

In my brass bucket there is a mostly non corrosive brass but there is some corrosive in there. How should I deal with that?

[Woodman in MO]

I'd leave the primers in there. otherwise you might get media in your primer hole, no big deal though.

What is corrosive brass?

[landtoy80]

<<<What is corrosive brass?>>>

OK, I mean I have brass from corrosive ammo.

[Woodman in MO]

<<<What is corrosive brass?>>>

OK, I mean I have brass from corrosive ammo.


I wouldn't worry about that. The corrosive part was the primer. Should clean up nicely. If you like shiny brass, you can add polish to the tumbler and it comes out looking pretty nice.

[rep30cal]

I tumble with the primers in, that way I am resizing clean brass because the
dirt and grit will scratch your dies. Some people have a seperate depriming
station, then to the tumbler, that way the tumbler takes care of a lot of the
primer residue left in the pockets, then it is ready to reload.

[nevada]

Walnut media will clean the dirty brass easily. Corn cob and a cleaner - I like Midways brass polish - should also clean them well. I've only used corn cob on my brass. Leave the tumbler on long enough and the brass will look like new. I like shiney brass. Nothing wrong with clean brass, but almost all of it will shine up. Even the military with dark necks will shine if left in the tumbler long enough. But I like the dark necks for military brass. I also leave the primers in until I reload the case.

The brain finaly kicked in: dark necks = annealing.

[Schultz]

If you add cleaner or polish to your media make sure it doesn't have ammonia in it, Ammonia weakens the brass over time.

[bigbear77]

With "corrosive" ammunition there are two failure mechanisms caused by two culprits: mercury and potassium chlorate. Mercury attacks the brass case through amalgamation. Potassium chloride (from the chlorate) accelerates corrosion of the steel rifle bore, just as salt (sodium chloride) would.

Early primers in the West contained mercury fulminate as the shock sensitive component. When they were fired elemental mercury was liberated. Black powder cartridges produced fouling which absorbed the mercury which was then flushed out during cleaning, end of story. Smokeless powder did not trap the mercury so it ended up amalgamating with the brass case, embrittling it, and leading to case rupture in a subsequent firing. While mercury is not corrosive, some claim that mercuric primers also contained compounds which caused corrosion. Some say they did not. Who's right? Beats me...

Potassium chlorate primers replaced mercury ones early in the 20th century in the US (anywhere from 1900 to the 1930s, depending on the source). Potassium chlorate primers used in US military ammunition were phased out by the 1950s or so. They were replaced by non-corrosive primers which utilized lead styphnate, IIRC.

Some countries still use potassium chlorate primers for their military ammunition. They have the advantage of being more stable than some non-corrosive primers at higher operating and storage temperatures. Militaries kept on using them and trained their soldiers to clean their weapons often, and with bore solvents specifically made to remove the corrosive salt(s) as well as powder fouling.

(That's probably more background than you wanted or needed to hear. If so, sorry about that...)

That being said, you have two things to consider: 1) if the cases you have were from VERY early on (1930’s or earlier) the primers may have been mercuric and the brass is unsafe, and should be discarded; and 2) if the cases were made in a foreign country (Eastern bloc?) there’s no guarantee what the primers may contain, and you might be wise to discard them to be on the safe side. (That is, “corrosive” may not mean “potassium chlorate” as with US ammunition.) Unless the cases are for very rare calibers or otherwise unobtainable, they might not be worth the risk. Besides, corrosive foreign primers are (in my experience) usually Berdan and (to me) not worth the bother to reload when so much surplus Boxer primed brass is readily available.

As for tumbling, I prefer to leave the fired primers in until I reload to ensure that the flash hole is not clogged with any tumbling media - the decapping pin makes sure of that. Just be sure that the cases are completely empty of tumbling media before reloading. Residual media in the case effectively reduces the internal case volume and increases pressures, sometimes dramatically. Not good.

Good luck, and be safe.

[nevada]

Boy was that more than I wanted to know!

Just kidding! It is good information.

[Schultz]

+1 on the good info!:thumbup:

[bigbear77]

Boy was that more than I wanted to know!



Well, once an engineer, always an engineer, I guess. Some habits die hard :wink:

Glad you found it helpful...

[robocop10mm]

As for the dried mud, rinse off the larger chunks and run it through the polisher. The smaller stuff will come off. I use 2 tumblers. The first has older media in it. It cleans the dirt and grime off. Then into the 2nd tumbler with fresh media and Flitz metal polish. This gives a nice bright polish to the brass. I then resize/deprime. If the brass is sized in a carbide sizer, I clean the primer pockets, inspect for cracks and load. If it was resized with a lube in a steel sizer, it goes back into tumbler 1 then 2, the primer pockets are cleaned and it gets loaded. Most of the brass that is non-carbide sized is bottle necked rifle brass and also gets checked for length and trimmed as needed. I also aneal the necks of all rifle brass larger than 5.56 mm. I don't bother to aneal the 5.56 as it is far more plentiful and I do not sweat it if the life expectancy is lessened.

[landtoy80]

The corrosive ammo I have if from the 50's up and is Eastern Block 7.62x39, 7.62x51 and 7.62x54R
My question is, does collecting the ammo in a bag and storing it in a box cause cross contamination between the corrosive and non corrosive brass?
Do I need to clean the non corrosive brass that stored with corrosive brass in a different way than normally?

[Rocky]

bottle neck cases are not carbide dies!

[nevada]

I can't see any reason for separating the brass depending on primer type, except checking for berdan/boxer types. It's not like there is a corrosive gas hanging around. If you want to set your mind at ease, wash the cases in hot water to neutralise any salts left in them.

He said most of the brass that is not carbide sized is bottle necked cases. That is correct. You can also buy noncarbide dies for straight cases, but I don't know why anyone would want to.

[robocop10mm]

bottle neck cases are not carbide dies!

HUH? The bottle necked cases are not carbide SIZED. Almost without exception bottle necked cases are resized in non-carbide (steel) dies and require lubricant. That lubricant should be removed before finish loading (certaily before shooting). Removing the lube in the tumbler before trimming and loading is easier than wiping off each round after loading.

[Signal9]

Should make that a sticky regarding primers.

[landtoy80]

Went to store and bought Lyman Turbo Case Cleaning Media "Rouge Bearing Nutshell".
The instructions on the Frankfort Tumbler called for untreated walnut shells for cleaning. I got treated nut shells with rough in it.
I want to use the nut shells for cleaning and then use corncob for polishing.

Should I not use the rouge nut shells for cleaning?
Is there a problem using dry or polish treated corncob after using the rouge treated nut shells?

[bigbear77]

Should I not use the rouge nut shells for cleaning?
Is there a problem using dry or polish treated corncob after using the rouge treated nut shells?

Rouge (sometimes called “jeweler’s rouge”) is ferric oxide (rust) and is mildly abrasive. Back before the modern polishes came on the scene, we reloaders would sometimes add jeweler’s rouge to our walnut media to reduce the polishing time for badly tarnished brass. (OK, sometimes I got lazy and did it for all my brass. So sue me.) While it did speed up the polishing process, there were two drawbacks. First, the rouge sometimes separated out of the media and caked up inside the case (changing the internal case volume) and/or the primer pocket (so primers didn’t seat properly). Second, any rouge left on the outer surface of the case would scratch it when it went through the sizing die. (The rouge is harder than brass but softer than the steel die, so the die was not scratched, just the case.)

We overcame these problems by doing follow-up tumbling in corncob media for about 15-20 minutes to remove any rouge still on or in the cases, and then inspecting cases to make sure it was all gone(easy to do, rouge is blood red and stands out pretty well). Most reloaders went away from rouge when the newer polishes came out to avoid these issues.

I have a Midway 1292 tumbler that is essentially identical to the Frankfort Arsenal one you’re using. I got it in 1984 and I’m still using it with some of the rouge-coated walnut media I bought in bulk in the mid-80s. Never had a problem in all that time...

IMO, if you are diligent about inspecting the cases and always following up with a corncob polish to get rid of any remaining rouge you should be good to go.

[landtoy80]

I did my first batch of brass in the tumbler using the walnut then corn cob.
The outside is shiny but there is still dark spots inside the case, on the inside walls and near primer.
Does the inside need to be as clean and shiny as the outside?
Do I need more walnut or corn cob time?

[nevada]

Inside: dark, chemicals. FIRE! PRESSURE!! IT BUUUURRNNNNSSS!!!!

Outside: not.

[bigbear77]

I did my first batch of brass in the tumbler using the walnut then corn cob.
The outside is shiny but there is still dark spots inside the case, on the inside walls and near primer.
Does the inside need to be as clean and shiny as the outside?
Do I need more walnut or corn cob time?

The inside of the case will never be as clean and bright as it was before firing. Ever. Nevada is correct, the combination of temperature and pressure bakes the combustion products onto (and probably into) the surface of the case's internal wall. Vibratory tumbling removes a lot of that residue but some will always be left behind. It's especially pronounced at the base and on the shoulder (you'll see that if you ever section a fired case to have a look). Even dedicated carbon cleaners won't get it all out. For my hunting and battle rifles I get the bulk of it out through tumbling, look to make sure there's no media left inside the case, and move on.

I shoot my 308 Win. Remington 700 in long range matches so I get a chance to talk reloading with the other benchrest guys. From experience they have learned all of the tips and tricks for getting maximum accuracy from their reloads. They turned me on to using a chemical bath in an ultrasonic cleaner, and I use it for the Lapua brass I use for match ammunition. Here's a good write-up on that technique: http://www.6mmbr.com/ultrasonic.html

I obviously don't go to all of that trouble when I reload for my battle rifle, and I'm not suggesting you should either. That would be a waste of time. But the article does have some good pictures which show that even ultrasonic cleaning doesn't get the inside of the case completely clean.

Hope this helps...