Mistreated Brass Appearance

[F. Guffey]

Again, I purchased 1,400 30/06 once fired cases from a flea market in North Carolina for $14.00 dollars, the dealer threw the bucket in for free. No one wanted to clean the cases, the cases had 30+ years of patina build-up on them. I cleaned the cases in vinegar for 15 minutes and then rinsed the cases in boiling water. In two hours I had all of the cases cleaned and then began tumbling, I tumbled the cases for one hour.

It will never be necessary to clean the cases in vinegar again but: the 15 minutes in vinegar is for the life of that case.

And I do not load ahead, some ugly things can go on between the bullet and neck when acid is used to clean cases; I understand, there are those that are exempt and or immune to what looks like two metals contacting each other that are not compatible.

F. Guffey

[hounddawg]

you don't have to worry about cold welding, 2 dissimilar metals cannot cold weld. I trust no one is shooting brass bullets from brass cases.

As long as there is no electrolyte present no galvanic action can occur either. Bullets also receive a polishing as one of the last steps in manufacturing, the wax would act as a insulator.

Go find some 50 year old ammo, odds are it will shoot as good as it did 49 years, 11 months, and 29 days ago

[F. Guffey]

you don't have to worry about cold welding,

I don't; that happens at arsenals, there is a difference between welding and dissolving, turning green etc..

At aresnals they have cold welding that goes up to 500 pounds of something. If they were experiencing bullet hold I would say; "now that is some kind of bullet hold". But they did not said anything about neck tension?

And then we had a member on this forum that checked one of his fired cases, it was missing the neck. He then went back and checked the last four cases fired and found the necks missing on all four cases.

F. Guffey

[hounddawg]

Guffy it is scientifically impossible for two dissimilar metals to cold weld under normal conditions. Just don't send your cartridges on the next space mission and they will be fine

[m&p45acp10+1]

Buy either the RCBS or Frankford Arsenal cleaner for wet tumbling and you will not have those problems. RCBS does not have to be rinsed off. Though I will warn you do not try to reuse it. It is not worth it. Half of the little bubble on the bottle full will do a tumbler full. No need to rinse it off at all. It will protect the brass from tarnishing as well.

The pouch of stuff that came with the tumbler kit worked like a champ, and that brass has no spots at all.

The other thing I have tried with good results was I started buy putting the brass in a jug with half a gallon of hot water, a teaspoon of white vinegar, and a shot of dish soap. Agitate for a minute or two. Let sit for 5 minutes. Shake the dickens out of it for about 2 minutes. Drain the water, and rinse a couple of times. Then I put into the wet tumbler with hot water, one half teaspoon of Lemishine, and one cap full of Rain-X spot free car wash. I rinse well after I take them out of the tumbler. At least 2 times. I use hot water. I use a spinning separator to spin as much water as I can get off of the cases, and to remove the remaining pins. (They come loose easier if coaxed with water.) I dry mine in a nylon paint straining screen. I hang it up on a patio chair in the sun. Brass does not fade, or spot that way.

[Marco Califo]

m&p45acp10+1
I have the FA. That was in the first post.
I also only use RO water. So, mineral "spots" weren't my issue, with this brass.
In post 25, I said I am tossing this brass lot, for the reasons stated there.

[Unclenick]

Marco,

I usually use 5% citric acid (your Lemishine is basically that, but more expensive; I bought 10 lbs postpaid for about $24 from Dudadiesle) and expose the brass to it until all oxide traces are gone. Heating to about 140°F in my Ultrasonic cleaner makes this very fast. I haven't monitored pH yet to see if I'm way overdoing the citric acid. I may be. I got that percentage from an old NRA article that said it had been the Frankford Arsenal brass cleaning solution at one time. Possibly in WWI. The decision to stop polishing for better corrosion resistance didn't come until the 1920's.

With extended corrosion time, at spots, the zinc in the brass will have oxidized preferentially, so that when the oxides are removed by the acid, you are left with a blemish in the form of a pink wash of surface copper. The surface copper wash, in turn, is so thin that it is easily tumbled off. I use the green Lyman corn-cob media to remove that stain, as it is faster than rouge, and is done in 20 or 30 minutes. It also produces a higher RMS surface finish, so it is not quite mirror shiny. You can follow-up with rouge to get a mirror polish if you like. After getting the pink out once, you will then be able to citric acid clean the case without the pink coming back.



My personal preference is for fairly bright yellow, but not mirror shiny. This is because my purpose is to make the brass as easy to spot in the grass as possible. At most matches the brass policing period is short, and tarnished brass ejected into the grass is effectively camouflaged. I also found out, when I tried nickel-plated brass for one match, thinking it would help me distinguish my brass from others, that a color-neutral mirror surface reflects grass-green, also camouflaging the brass in the grass. Mirror polishing brass-colored brass is not as bad, but it's not as good as a bright, dull yellow. If I could make brass a fluorescent color, I would.


Hounddawg,

You are missing some information on bullet cold welding. The first piece is that the gilding metal bullet jackets are drawn from is a form of low brass. It's about 5% zinc and 95% copper. The brass cartridge cases are made from basically just have a higher zinc percentage, giving them their yellow color, among other property differences. But they are both forms of brass and not completely dissimilar metals.

Second, cold bonding isn't caused only by galvanic processes. Even in a high vacuum, where oxygen and moisture are practically absent, two alloys containing one common constituent metal can exhibit some degree of cold bonding when pressed together for enough time. Physicists think it's because atoms of the common metal, at points of intimate contact between the surfaces, can, at the quantum level, become confused about which of the two kissing alloys they are actually part of. Once atoms are shared like that, separating the surfaces means pulling the trouble-making atoms out of one of the alloys, increasing the effort required.

Board member Hummer70, who was a test directory at Aberdeen Proving Grounds, said they had an instrument for measuring bullet pull and that he had measured as much as 600 lbs of pull on some 20-year-old 7.62 cartridges that had been properly stockpiled. These had about 60 lbs pull when they were new. That is still much less than normal start pressure, though, so it didn't affect their ability to fire. It would have increased peak pressure value a little. In QuickLOAD the pressure increase in a .308 Win from the extra 540 lbs of pull is around 1.5-2% depending on the bullet weight and charge level.

This phenomenon is well enough known that SAAMI actually has a spec for it called the Maximum Probable Lot Mean (MPSM). It is about 6% higher than the Maximum Average Pressure we usually see listed as the upper-pressure limit, but which SAAMI uses only for newly minted ammunition. The MPSM is a pressure limit for future samples from the lot during its whole lifetime.

Third, cold alloying between different metals can also occur if the required added energy is low enough, which is another way of saying the solubility of one metal in the other is high enough. Hatcher gives the example of tin-plated bullets used in National Match ammunition one year in the early 1920's. It was an attempt to cut down on copper fouling. Back then, bullet jackets were cupro-nickel alloy instead of a brass, and these tended to build up copper in lumps in a bore, so preventing that build-up was desirable for consistent performance both as to pressure and accuracy. They made and tested the plated bullets and all seemed well, so they manufactured the year's supply. When it arrived at Camp Perry and was issued for the matches, it was a few months older. Not only were pressure signs high, but some cases were ejected with the whole cartridge neck missing. The pit crews recovered bullets with case necks still attached and with rifling marks extruded into them. So this was actual cold soldering. Tin and copper make bronze, and apparently, some formed at the interface.

It's a world full of weirdness out there.

[hounddawg]

UncleNick

with all due respect cold welding of a bullet to a case would have to take place in a vacuum and they would have to be perfectly clean with no oxidation, or lubricants or waxes on the surface. That is just the way it works. Feynman did a series of lectures on it because of the impact it had on space projects. Some of the failures with satellites operations were due to cold welding where it wasn't wanted.

why SAMMI has a maximum probable lot mean has nothing to do with welding of any sort. Think of it as the SD's and ES's when chronoing your own ammo.

this link which will explain it better than I can

Because it is impractical to obtain the true average for a given set of loads (you would have to shoot all of them), SAAMI established guidelines to assure safety when a cartridge manufacturer develops a load within the MAP and subsequent testing of production lots. The Maximum Probable Lot Mean (MPLM) and the Maximum Sample Probable Mean (MPSM) are used for assessing whether a particular lot of ammunition can be accepted or rejected. Our principal concern in this paper is load development rather than process control. Should you be interested in learning more about MPLM and MPLSM, try a Google search for “SAAMI Standard – 206(1)” and the first item popping up will likely be a downloadable PDF of the standard.

http://shootersnotes.com/articles/saami-pressure/

on some of the other points

I suspect why the bullet pull force may be slightly more on ammo that is 50 years old vs some made yesterday probably had to do with the formation of cupric oxide forms on both brass and copper. The is the reddish looking oxides on the piece of brass in your post is cupric oxide. When you clean heavily oxidized brass with acid it will remove the cuperous oxides which are the blackish greenish oxidation but not the pinkish red oxides which are cupric.

I could see where there could be some adhesion of oxide layers when both the brass and the copper form a thin layer of cupric oxide. But that would not be a welding of the metals

[Unclenick]

I haven't seen that article before, but I got my information straight from the horse's mouth. The Maximum Probable Lot Mean covers the statistical error you are referring to for the purposes of developing a load to manufacture. The MPSM applies only to ammunition after it has been manufactured, which is how it comes to include covering aging effects during subsequent sampling. It's not the only thing it allows for, as there is the 2.5% of the population randomly outside of the MPLM, assuming a normal distribution, as SAAMI does, and the storage conditions and other factors that could affect an ammunition lot later, but it's also a larger difference than is necessary just to account for bullet bonding.

From ANSI/SAAMI Z299.4 – 2015, p. 8

"Maximum Probable Sample Mean (MPSM) - is the maximum expected average pressure that may be observed in the testing of product subsequent to its manufacture and is not intended for use as a loading control point."

Another example of SAAMI concern over pressure change with aging is the protocol for reference ammunition. Even though it is stored and, for testing, conditioned in standard ambient conditions, samples of each reference lot are sent back around to member test facilities every two years for retesting to allow for gradual shift in its pressure and velocity values for the lot. What makes this fact useful is the 2-year timeframe suggests bonding doesn't change very significantly in that period, but longer periods can be otherwise.

Originally Posted by houndawg

…the bullet pull force may be slightly more on ammo that is 50 years old vs some made yesterday…

The problem here is theoretical versus measured. You can PM Hummer70 if you don't believe it, but he used government equipment to measure an order of magnitude difference in bullet pull force in some instances. I have personally torn the neck off a round of .30-06 trying to pull the bullet (don't know the exact age, but decades, anyway, and trying the trick of seating it deeper first just buckled the shoulder). The powder inside appeared and smelled OK. So, whatever theoretical explanation we can get comfortable with needs to account for these measured and observed facts. I can tell you to a certainty that deteriorating powder will oxidize-bond a case to a bullet and even corrode a hole through it, to boot. I have some examples of that. But Hummer70's rounds test-fired normally and I don't believe they were past their stockpile expiration date (that should be double-checked with him), so they weren't in that situation.

When a bullet is seated in new brass or into a case mouth that is freshly chamfered, the surface of the bullet is scraped clean on its way in and the brass in the neck gets scuffed, too, so oxide-free friction contact between the two surfaces likely occurs at some places. What percent of the area is involved, I don't know, but would expect a smallish fraction, and it may do pretty well at squeezing out and excluding air from some portion of that. How well or long it is able to remain clean, I have no idea. What I can tell you, to provide a sense of the effect, is that twenty odd years ago I trimmed and chamfered a .223 case and seated a moly-coated bullet in it, then pulled the bullet in an inertial puller (I don't recall why) and was surprised to see completely bare copper uniformly below the case mouth line with longitudinal scuff marks down the length of the whole bullet bearing surface. The inside of the case neck looked similarly scuffed. I've also had new commercial ammunition where there was an actual small ring of copper scraped up around the case mouth where the bullet emerges from it and as you more normally notice with lead bullets seated in an inadequately flared case. From its size, I recall figuring that something on the order of a quarter thousandth of bullet surface had been scraped clean off during seating.

All this varies substantially with manufacturing and component handling practices, residual lubricants, and so on, but all the possibilities have to be allowed for. I'll have to repeat that scraping experiment with a new case that has neck annealing stain inside and out to see how clean the inside of the neck looks afterward. If it stays dark, that is a sign you are right that oxygen exchange and bonding is contributing some portion of the bond, especially in military cases.

I feel dumb not having considered cuprous oxide as the source of the pink color. I just assumed that since all oxides of copper are acid-soluble that it was gone. But on reflection, it may just be they are all soluble in the mineral acids and hydrochloric and nitric and etc. I've forgotten. Obviously, there isn't any zinc left there, though. You can see the zinc damage as a white oxide that crumbles off the outside on a badly corroded case, as well as ther verdigris (peroxide?). I seem to recall that cuprous oxide reduces to cupric oxide, but that may be only at the surface, making appear black when it isn't solid black.

It occurs to me that galvanic bonding, though the two alloys aren't identical, is still in the offing. The Norma manual shows that water molecules still pass through the bullet/neck interface. It mentions that if you change the relative humidity a cartridge is kept in, over a period of about a year, the water content of the powder in the case will match that of powder kept outside it in those same conditions. I don't know how much difference sealants make. It will be significant, but none of the sealants I've seen are anything but single resins of one kind or another, and those all have measurable permeability rates for water vapor and other air gases.

[hounddawg]

@UncleNick

I am not saying that some sort of adhesion or cohesion takes place over the years and causes neck tension to increase. I can think of several culprits such as oxidation forming on the bullet and case or more liklely wax or lubricant from the manufacturing process drying out.

Galvanic action would need an electrolyte present, and yellow brass and copper are so close together on the nobility scale any electrolytic effects would be minor. As a marine mechanic I dealt with galvanic corrosion on a daily basis almost. If in your experiments you notice pitting of the brass where it contacted the copper then you may be seeing galvanic action. Without an electrolyte present it is doubtful you will see any. Seat a bullet in a case with a spent primer and let it sit in a salt water bath for a couple of weeks then pull the bullet to see see if any penetrated between neck and bullet. That would accelerate any galvanic action occurring from humidity over the course of years. You should see some on the exterior of the case unless there is a wax or oil acting as a insulator, but I don't think there would be any on the inside of the neck

I think what is happening here is people are misusing the term cold welding. What is really happening is that the bullets and case are bonding through either cohesion with the oxidation process or adhesion from the wax or oils from manufacturing starting to deteriorate. I would put my money on adhesion before anything else. I have shot 50 year old plus ammo, I was not looking for problems but none found me either except the odd bad primer.

Molecular level cold welding only takes place under very controlled conditions. You will not find those conditions on a reloading bench or in a ammo bunker.

[briandg]

Just throwing this out there, I have read several times of .03 ammunition that had been tinned. Between the brass alloy, the gilding metal alloy, and that very insignificant tin wash, there were supposed to have been problems with what was described simply as "sticking in the case neck". It's not inconceivable to me that molecules of copper and tin would migrate into the adjacent masses of material and bond to the "other side" of the compressed assembly.

What I have always understood about vacuum welding is that it takes place when there isn't a significant layer of anything to keep the individual molecules from touching, and under the circumstances, with molecules in such intimate contact, a few bonds will switch alliances..




There is no reason wny a similar process to vac welding can't take place in plenty of situations. The atoms in any material are promiscuous, they will get into bed with damned near anything. The electrons will be willing to slip to another bond.

We have machines that laminate metals through use of nothing but high impact compression. No mechanical bonds, just smashing the two metal parts together with such force that you wind up with the two things bound together at the atomic level. Much like growing a crystal.

[F. Guffey]

Just throwing this out there, I have read several times of .03 ammunition that had been tinned.

I do not have any 30/06 cases that have been tinned but if there was a plan to reuse a case as in hand load and or reloading back in the old days there was no choice, the case had to be tinned on the inside. It has something to do with infinity. In the old days mercury was used, I know, it does not seem like a problem but when the brass case was fired it became brittle, it did not take an hour, the moment the case was fired it was scrap.

I have pulled down many cases for different reasons, I have never found a case that had the bullet welded to the case neck. I have pulled down thousands of Cuprio? nicked bullets that were loaded in 1938 and 39. All of those cases had corrosive primers.

I have pulled down thousands of handloads that were loaded in the early 70s, some of the cases would have fired, I pulled the necks off of some of the cases with my hands. The powder had gone bad in other cases. I have close to 2 30 cal ammo cans full of AP pulled bullets from M1 Garand ammo without one welded neck.

And then there is the equipment for pulling bullets and the time factor. The case neck expands to release the bullet when fired. One more time; we had a member on this forum that fired the fifth round of a set he had loaded, he inspected the case' the case did not have a neck. He then went back and checked the first 4 he fired and found all of the necks missing. I never wondered if the necks were a little slow on the expanding sequence of events.

He did say he was going to quit taking advise from reloaders on the Internet.

F. Guffey

[F. Guffey]

And then there was the 'Tin Can deal', I have a few of those, I will not pull the bullets nor will I fire them. I call the cuprio nickel bullets 'streakers'. There are a few old articles about streaker bullets and the difficult in cleaning the barrels. The last article I saw was printed in 1953 with a few helpful hints.

Greasing your chamber, case bullet and barrel was not in the helpful hints section.

F. Guffey

[hounddawg]

tin can ammo had nothing to do with "cold welding" of bullet to case. I underlined and bolded the important part

One of the most immediate problems facing both the Ordnance and the individual shooter was the tendency of then-current service ammunition to foul the interior of a rifle's bore. Bullet jackets at that time were drawn from an alloy of copper and nickel (cupro-nickel). This alloy had been in use since the development of ammunition for the Krag-Jorgensen rifle of 1892, but until the army switched to the Model 1906 cartridge with its 150-grain bullet at a velocity of some 2,700 fps (specifications called for an instrumental velocity of 2,640 fps at a point 78 feet from the gun), there were no significant problems. The velocity of the 1906 cartridge, however, was above the threshold at which the heat and friction of firing neatly soldered small amounts of the bullet jacket to the interior of a rifle's bore. Once this jacket fouling began to build up, it tended to build on itself and, in very short order, the barrel filled with lumpy fouling and accuracy quickly deteriorated. To compound the problem, removing the cupro-nickel jacket fouling risked permanent damage to the bore

https://www.ssusa.org/articles/2016/...l-matches-1921

[hounddawg]

Unclenick

It occurs to me that galvanic bonding, though the two alloys aren't identical, is still in the offing. The Norma manual shows that water molecules still pass through the bullet/neck interface

you nailed it UncleNick... I spent a rainy morning researching this and electro chemical bonding is what was commonly and mistakenly referred to as cold welding.

Whelen's idea of using zinc coated bullets accelerated the galvanic process due to the low nobility of zinc compared to yellow brass. It did solve the problem of fouling and in most cases the bonding did not present any significant problems and supposedly the ammo shot really well. It was what George Farr used in the 1921 nationals and shot 71 consecutive bulls with

This is not something we need to worry about unless you start coating your bullets with or casting from zinc and then storing them for months and years. It is just another one of those interesting tidbits of history of the shooting sport.

thanks for a great discussion guys, this was my learned something new for the day

[F. Guffey]

The velocity of the 1906 cartridge, however, was above the threshold at which the heat and friction of firing neatly soldered small amounts of the bullet jacket to the interior of a rifle's bore. Once this jacket fouling began to build up, it tended to build on itself and, in very short order, the barrel filled with lumpy fouling and accuracy quickly deteriorated. To compound the problem, removing the cupro-nickel jacket fouling risked permanent damage to the bore

And then there were those streakers, and the last time I saw anything written about that was in a book about 1953, those streakers would lump up the barrel and cleaning had to be reinvented.

F. Guffey

[F. Guffey]

forgot, that was about the time they started lubing their bullets, cases and chambers.

F. Guffey

[JeepHammer]

Chemical cleaners attack brass. Period.
Some evaporate and don't have to be removed or neutralized, some do.
Residue from evaporation will usually activate when moisture is introduced back to it.
Chemical cleaners are chemically 'Reactive' (go figure!) with the base metal or alloys, sometimes attacking the corrosion first or more efficiently than the base metals.

Notice in the image above of the pistol cases how pitted the 'Clean' brass is?
This is the result of the acid used attacking the base brass alloy...
Reactive agents MUST be nutralize or removed, no matter how weak the concentration you use.

Guys using too much 'Lemi-Shine' find this out quickly! It changes the color of the brass, and brass not flushed through (or a base used to nutralize the acid) find out Lemi-Shine WILL attack/corrode brass.

'Rouge' is an abrasive, commonly meaning, it's harder than the material it's being used on.
Abrasives of any kind leave small scratches,
Scratch size depends on the size of abrasive.
'Rouge' is usually a very fine abrasive in a binder, like wax.
Scratches determine how 'Smooth' or 'Shiny' the material 'Looks' since scratches refract light away from the eye, all color being reflected light back to the eye.
Less light gets reflected back to the eye, brass looks 'Duller'.

Polish medias are commonly SOFTER than the material being worked.
They DO NOT scratch the base material, but can be harder than the corrosion on the surface of that material.

Walnut shell (in particular English walnut shell) is just under the hardness threshold required to remove brass, can't scratch brass, but harder than corrosion coming from brass (common oxidation, some chemical corrosion can be as hard, or harder than the brass itself).

You can leave brass rattle around in walnut shell endlessly (some of us have) and the base brass alloy will still be a 'Case' when you get back to it, it doesn't turn into powder in the bottom of the tumbler like it would with an actual abrasive.
I forgot cases rattling before, rattled days, once two weeks, and the brass was REALLY clean, but still fine to use (and my media was past dust, it was a fine powder after two weeks).

Coatings.
What people commonly refer to as 'Polish' is actually a Coating, like a wax.
Coatings fill in fine scratches & have a higher light reflective index than the actual brass.
The higher reflective index makes coating appear 'More Shiny' than the base brass actually is.
(Clear coats on automotive paints is an example)

[F. Guffey]

Chemical cleaners attack brass. Period.

That is what I said. I said I started out with a potion that reduced the time to less than 2 minutes with 2 rinses in boiling water. When finished the cases turned black, we called it 'pickling' because it was a method for storing cases. And then? Because vinegar was safer and slower I went to vinegar and nothing; I continue to rinse in boiling water and only clean the worst of cases 'once' in vinegar.

F. Guffey

[briandg]

Guffey, I probably didn't say that as clearly as I should have, the things that I was writing about were just the bullets, and god knows how long ago that was. It was described as just a light tin plate, nothing heavy, probably just to prevent some corrosion. It may be that they were also cupro underneath, there's a lot of that information that I don't remember, and it was just a short paragraph.

I had forgotten about the cupro streaking, I remember reading that sometimes the things were so badly fouled that the gun would blow.

Another thing that I read, really kind of ridiculous, a guy was going on about lead bullets being unsafe. Adding tin to lead makes solder, right? beeswax and resin are used as flux, right? Well, he thought that every time a gun was fired with a tin alloy bullet, that Solder and flux would plate to the bore. I don't think that it worked that way.

Does anyone remember the zinc harvey bullet? the history of this stuff is amazing.


http://hawkbullets.com/prot-x-bore.html