Corrosion Like I Have Never Seen

[Ole 5 hole group]

It might help some people to just google gunpowder shelf life and do a little reading. I don't doubt slamfires comments or experiences - his experiences are just different from mine and all the shooters that I have known. I also have no idea why some commerical ammo goes to hell in a hand basket.

One example I'll mention is Hodgdon powder, namely the H4831 was 1st on the market back in the 1950’s and to my understanding was actually military surplus powder made back in the 1930’s. There are some people still shooting that “original” powder and it is performing as good today as it did back in the 1950’s.

I think Hodgdon ran out of that particular military surplus powder back in the ‘70’s and thereafter labeled their containers “newly manufactured” and that powder was sold in the ole paper container colored red & black with a black plastic cap. That "newly manufactured" powder is still going strong today.

I have never come across any smokeless gun powder that smelled “good” regardless of age, that didn’t perform as expected. In all my years of reloading, I’ve only come across one case of IMR-4350 in the brown metal can with red cap having white & brown lettering that went bad while stored in ideal conditions for about 20 years. When given the sniff test it failed badly!! I suspect it was the containers that broke the powder down, as I had some of that powder from that particular case stored in my "plastic pharmaceutical pill reloading bottle" that never went bad and it's is still good today.

In my opinion, most smokeless gun powder will outlive the user if stored in “reasonable” conditions over the years and all that is needed to determine if the powder is good or not is your sense of smell.

 

[gyvel]

Could steel have caused a reaction with the powder?

Dissimilar metals?

 

[Salmoneye]

In my opinion, most smokeless gun powder will outlive the user if stored in “reasonable” conditions over the years and all that is needed to determine if the powder is good or not is your sense of smell.

While I have agreed with this for decades, I must rethink my stance as pertains to 'vintage' loaded ammo...

Some of the cartridges I disassembled had no outward appearance of problems, but internally were a different story...

And there is no way to give them a smell test...

 

[Grizz12]

This is a GREAT thread and explains why my buddies old rifle in 30-06 blew up on him when we were shooting his granddads old ammo. We shot boxes of the stuff with no issues and these rounds didnt look any different from the others.

Lesson learned then and 20+ years later I know why it happened.

 

[Mike Irwin]

Yes, Hodgdon got its start selling surplus powder.

It wasn't from the 1930s, though, it was military production surplus from World War II.

And I have seen batches of that powder that has gone bad.

There's simply no realistic test that can tell us just how viable older powder is. The military may have such tests, but I suspect that they are beyond any of us, unless we have a full chemical engineering lab at our disposal.

There's a good reason why the military surpluses ammo after a certain number of years -- because from their own research and experience, they KNOW that powder degrades over time.

I used to think of powder as being an ageless thing unless it was stored in absolutely abysmal conditions.

It's not.

I have hundreds of rounds of ammunition in my personal collection, many of them from the dawn of the smokeless age.

They all seem to be viable. I've even cracked some old (really old) cartridges.

The powder SEEMS to be OK, but again, without that lab set up, I have no clue what's going on with that powder at a molecular level, nor am I going to make any bets.

I'll probably even keep shooting old surplus ammo from time to time, but I'll be a lot more circumspect about it than I used to be.

 

[Slamfire]

Could steel have caused a reaction with the powder?

Dissimilar metals?

Rust most likely. As nitric acid gas comes out of the powder it causes rust.

As nitric acid gas comes out of the powder it causes rust. Rust is an ionic compound and all ionic compounds interact with the double bonds on nitrocellulose , breaking them, and releasing NOx. Nitroglycerine also interacts with those double bonds which is why double based powder have a lifetime less than half of single based. Water is bad for several reasons. I found a paper in the 30’s where water dissolved some of the gelatinizing compounds in gunpowder and caused micro cracking of the grains. Water is a polar covalent ion and acts ionic, the big oxygen atom at the end interacts with double bonds and breaks them. Water in the air also has the unfortunate effect of condensing and evaporating on the powder grain, and when water evaporates it wicks nitroglycerine to the surface. I met a gentleman who had been to a small rocket motor recertification facility. These were old, Korean war or earlier, rocket motors used for sled track purposes. He saw the workers scrape off nitroglycerine off the surface of the opened motors. While these motor were old, they were are unique in their size and availability. They also periodically blow in tests. While unfortunate, these are not manned tests, and the tradeoff is, no test, or a test with a probability of rocket failure. At some point, obviously, the rockets get dumped, because no one wants to fund a test with a 50-50 chance of failure. They don't want to fund a test with a 5% chance of failure either. When the surface of any powder becomes nitrogylercine rich, that will spike the initial pressure curve.

So while it does not make sense, you would expect that gunpowder as it breaks down, would loose energy, and thus go benign, and the last part will eventually happen, but even as it is losing energy, it is changing its burn rate characteristics. That is what spikes the pressure curve.

Mechanical deterioration, which you see in the pictures, that dust which results, is very bad. Increasing the surface area will vastly spike the pressure curve. You would think coal is low energy compared to gunpowder, and it more or less is, but grind it into a dust, and a coal dust explosion is real impressive, and dangerous.

Coal dust explosion in container

http://www.youtube.com/watch?v=8Cdhm024-10

Coal Dust explosion, industrial level:

http://www.liveleak.com/view?i=09e_1241559869

Suppressed versus unsuppressed coal dust explosion.


http://www.youtube.com/watch?v=czUUlJQ_9LE

http://www.mineweb.com/mineweb/content/en/mineweb-technology?oid=157297&sn=Detail

In my opinion, most smokeless gun powder will outlive the user if stored in “reasonable” conditions over the years and all that is needed to determine if the powder is good or not is your sense of smell.

I don’t know if it is that easy. There are literally thousands of insensitive munitions experts working this issue for the various first world Militaries. Search the literature and see all the tests they have developed. They, unlike us, also have access to expensive chemical labs and I think, if it was that easy, they would be simply smelling the powder. The rest of us, without chemical labs, all we have is our sense of smell, taste, sight, touch. I have some 1898 Krag cartridges and the powder is red, and in the dark, you can see the stuff glowing red, like tiny charcoal briquettes. There is not enough powder in a single case to smell anything. Surplus IMR powder that did not have a smell in the keg, still black in color, went bad in a couple of years, I had corrosion, case neck splits, pressure indications. I am now suspicious of any powders that are neutral in smell.

All I really want to do is inform the community that gunpowder does not last forever, understand the mechanisms, to the best of my understanding, of how gunpowder breaks down, what to look for, and to understand that old ammunition has its risks. I would recommend to all, if you experience pressure indications with old ammunition, if you see corrosion, stop shooting the ammunition, dump the powder, save the bullets. I would inspect the cases for evidence of corrosion, and then I would ponder what to do with the cases. No corrosion would be a good thing, and as I am cheap, I might reuse them. I might be spooked by another’s experience and toss them all out. I could go either way.

There's a good reason why the military surpluses ammo after a certain number of years -- because from their own research and experience, they KNOW that powder degrades over time.

FYI, these came from a 1969 and 1970 Insenstive Munitions Symposium:

 

[maillemaker]

Interesting - I was just reading today that when the USS Iowa's main battery exploded back in the 80's or 90's or whenever it was it is though that the culprit may have been powder manufactured in the 1930s.

Steve