Does annealing change over time?

[savagedasher]

Brass will stress crack with age. Cause is the ammonia that is in the air. Cases are prone to cracking from the ammonia in the powder.
Larry

 

[gotcha]

For whatever this is worth, Remington and Federal both state in their FAQ's "loaded ammunition has a 10 year shelf life on loaded ammunition" -if stored properly. As for Lapua "at least 5 years"

Reading between the lines I suspect the "welding" of bullets to cases may have something to do with the above warnings as pressures could increase drastically......... Question: If one were to put such ammo in a press and break the corrosion bond by simply seating bullet a few thou. further into the case would this render the ammo usable? ............ BTW Thanks to all for the insightful info posted here. I've got a LOT of reading to do

 

[riflewoman]

Brass will stress crack with age. Cause is the ammonia that is in the air. Cases are prone to cracking from the ammonia in the powder.
Larry

Then why did the CMP issue 1960s 30-06 ball to our CMP club for issue at our CMP matches in the 1990s. The ammo was 30 years old and it shot fine and the brass reloaded fine.

So we have an anecdotal experience of some individual who had some 1940s ammo of completely unknown manufacture and storage fail. And now we are to believe that ammunition will destroy itself in a decade when people who have worked in the field of metallurgy, the American Society of Metals, etc. say otherwise?

 

[savagedasher]

Then why did the CMP issue 1960s 30-06 ball to our CMP club for issue at our CMP matches in the 1990s. The ammo was 30 years old and it shot fine and the brass reloaded fine.

So we have an anecdotal experience of some individual who had some 1940s ammo of completely unknown manufacture and storage fail. And now we are to believe that ammunition will destroy itself in a decade when people who have worked in the field of metallurgy, the American Society of Metals, etc. say otherwise?

It's in how it's stored just like powder . Larry

 

[370bc]

Reading between the lines I suspect the "welding" of bullets to cases may have something to do with the above warnings as pressures could increase drastically......... Question: If one were to put such ammo in a press and break the corrosion bond by simply seating bullet a few thou. further into the case would this render the ammo usable? ............ BTW Thanks to all for the insightful info posted here. I've got a LOT of reading to do

In my experience of having bullets weld to the brass has to do with my human sweat and not using rubber gloves. I now use rubber gloves and use dry graphite on the inside and outside of the case necks. If I touch just one bullet and put it back in a mostly full box, the whole box of bullets will become tarnished. That amazed me when I saw that.

 

[jlow]

Going back to the OP, the idea that neck tension can change over time does not necessarily mean that it can/will result in neck splits. We can all see why the link may exist but it is really a conjecture and not proven. One can happen without the other.

 

[LHSmith]

What specific information is your Norma link referring to? If you follow that link, it has the following statement about their brass:

"The case neck is annealed to become softer. This prevents gas leaks and enables the case to hold the bullet firmly for at least 10 years without cracking as a result of aging material."

In my mind, it would appear from this statement that Norma actually agrees that annealed brass is stable for a long time (at least 10 years). Not trying to stir the pot, just asking for clarification purposes.

I interpret it to mean their brass can be expected to have a usable shelf life of 10 years minimum ONCE it is loaded. I nor no one else claims cartridge brass work hardens sitting on the shelf if stored properly.

 

[Mozella]

..........snip........... I nor no one else claims cartridge brass work hardens sitting on the shelf if stored properly.

Perhaps people don't use the term "work" hardening associated with long term storage, but there are plenty of people who believe (incorrectly) that cartridge brass "age" hardens over time to the degree that cases which are, let's say, 50 years old can be expected to crack when loaded and fired. As far as I know, there is no scientific evidence that cartridge brass will "age harden" to any measurable degree over 50 years time. If this evidence exists, I wish someone would point me to it.

 

[Brians356]

If you want to avoid copper jacket "bonding" to brass, burnish the case mouth with 0000 steel wool, size neck ID .001" under bullet OD, and use moly-coated bullets.

 

[Webster]

My ASM book will prove both of them wrong, this is 100% wrong, right from Norma too "The case neck is annealed to become softer. This prevents gas leaks and enables the case to hold the bullet firmly for at least 10 years without cracking as a result of aging material.". Norma obviously had someone who wrote that who has a BA degree.

I posted a while back about stress corrosion cracking (season cracking) and about galvanic corrosion can occur with 2 dissimilar metals. You need 3 things for it to occur, an electrolyte, 2 different metals and electricity, but the exchange of electrons from the least noble metal will create it's own electricity. Cracked necks are 99.99% of the time from the de-zincification of brass, no amount of annealing will fix them.

To the OP, you can anneal your case today and 1,000 years from now the brass will be the same grain structure as it was the day it was annealed, assuming you control it's environment.

"99.9% of the time necks crack from de-zincification". If de-zincification did take place the surface would be highly textured, it is not textured. A dezincified piece of brass is highly textured and looks like a sponge at 100X magnification. I think dezincification would have to take place in a long term wet environment.

From all the discussions it appears that bullets bonding to the necks are from some type of general surface corrosion? Not stress corrosion. Some smokeless powder has more residual acid than it should because it wasn't properly removed after reacting acid with cellulose. Sounds nasty. Necks crack from repeated firing and sizing which cold works the neck to the point of cracking. It's like taking a piece of wire, a paper clip or a coat hanger a bending it back and forth until it breaks. I did failure analysis on broken copper wires soldered on electric motors in the Mark 48 torpedo. Vibration from the main engine, running for a short amount of time, cold worked the wires until they broke in two.

Is it possible for us to put together in one place when we have trouble with "cold welding" and people that think they never have cold welding. From this table or list figure out for once how to prevent welding even if we don't know the exact cause?

I think we need to drop the subject of annealing. Everyone that can read should know how to do it by now.