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Powder shelf life?

Discussion in 'Handloading and Reloading' started by Henry45, Dec 6, 2012.

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  1. Henry45

    Henry45 Member

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    Have been doing alot of reading, and some people claim there is a powder shelf life. I reloaded 25 years ago, and had to let it go but have gotten back into the sport in the last year or so.

    What have ya'll found? Is it true? If you bought powder today, kept it in proper locations in the original containers, out of all the heat/cold/moisture, what would you say today's powders shelf life is?

    I would think probably 25-30 years if not longer. What do you guys who have done this for years think?

    Is this one of those, "sake of discussion" issues that people bring up, or is it anything viable.?
     
  2. USSR

    USSR Member

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    The same as the shelf.

    Don
     
  3. tightgroup tiger

    tightgroup tiger Member

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    I have 30 yr old powder here, rifle and pistol both, I still load it and can't tell the difference between it and new powder.

    As long as it doesn't smell funny, (acid smell) and hasn't started turning red, you should be ok. If it is taken care of it will last a long, long, time.
     
  4. 45lcshooter

    45lcshooter Member

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    A lifetime, correctly stored. I have powder from the 1960's that i got from a buddies dad that i still use everynow and then.
     
  5. AlliedArmory

    AlliedArmory Member

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    There is no actual date on this, but if you still have powder from 30 yrs ago for anything other than decoration you need to load it!
     
  6. Offfhand

    Offfhand Member

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    The ammo I fired in the 1000 yard Wimbledon match at Camp Perry was loaded with H-4831 I bought back when it was .50 cents per pound and made about 70 years ago. The powder and I did very well.
     
  7. JohnM

    JohnM Member

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    Very cool. Properly stored powder has an incredibly long useful life.
     
  8. DurangoKid

    DurangoKid Member

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    I had talked to Dupont on the orginal IMR 4831. The information that they had was a 30-35 year shelf life on the IMR 4831. Back in 1973 we tested some old powder and found the products to have poor ignition and burn rates. :)
     
  9. G11354

    G11354 Member

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    Generally if it still smells like solvent it should be usable.
     
  10. JohnM

    JohnM Member

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    There's always gonna be examples going either way.
    I've got several that I'm sure are now something over 60 and they perform as if brand new.
    But, then not too long ago I tried another I think was no more than maybe 15 and it was no good.
     
  11. Slamfire

    Slamfire Member

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    From what I had read on the internet, which is a repeat of what is said in gun magazines, powder has an “indefinite” shelf life. Remember reading statements to the effect that powder lost energy as it got old, making it essentially benign.

    Then I ran into an Insensitive Munitions expert. This IM expert explained that powder deteriorates from the day it leaves the factory.

    Nitrocellulose decomposes through the reduction-oxidation process. Called Redox. The expert said “The molecular stability of the functional groups on the organic chain determine the life time of the nitrocellulose molecule.” All ionic compounds, water is the main offender because it is always in air, react with those bonds and accelerates the deterioration of the powder.

    The bottom line is that nitrocellulose is a high energy molecule that wants to become a low energy molecule.

    Heat accelerates the deterioration/decomposition of powder and the rate is directly proportional to the Arrhenius equation. If you read in the Insensitive munitions literature, you will see that they use high temperature to accelerate aging of smokeless propellants.

    ROLE OF DIPHENYLAMINE AS A STABILIZER IN PROPELLANTS;
    ANALYTICAL CHEMISTRY OF DIPHENYLAMINE IN PROPELLANTS
    http://www.dtic.mil/dtic/tr/fulltext/u2/783499.pdf

    Heat, as you can see in the report, will age gunpowder

    Propellantaging.jpg


    Combustion pressures will rise after high temperature storage.

    Pressurevariationsduetostoragetempertures-1.jpg



    Double based powders have a reduced lifetime compared with single base. Double based powders have nitroglycerin (NG) in the grain. Nitroglycerine remains a liquid and it migrates within the grain to react with the NO bonds on the nitrocellulose, increasing the rate of reduction-oxidation reaction. All ionic compounds react with those bonds and accelerate the deterioration of the powder. Rust is bad as ferric oxide is ionic. Water is polar covalent ion and is ever present in the air.

    The best storage condition for powders is arctic. Cold and dry.

    Due to the migration of NG within double based powders, the surface of the grain will become rich in NG even though the total energy content of the propellant has decreased. This will cause changes in the burn rate, and can cause pressures to spike. The surface of nitrocellulose powders also change as the powder deteriorates, and it changes unevenly. This creates conditions for erratic burn rates. Burn rate instability is undesirable and can cause explosive conditions in firearms. It is an extremely rare occurrence, but old ammunition has caused rifle Kabooms. When I discussed this with a machine gunner buddy, he said that explained the two top cover explosions he had with old Yugoslavian 8 MM ammo.

    Section from the Propellant Management Guide:

    Stabilizers are chemical ingredients added to propellant at time of manufacture to
    decrease the rate of propellant degradation and reduce the probability of auto ignition during its expected useful life.

    As nitrocellulose-based propellants decompose, they release nitrogen oxides. If the nitrogen oxides are left free to react in the propellant, they can react with the nitrate ester, causing further decomposition and additional release of nitrogen oxides. The reaction between the nitrate ester and the nitrogen oxides is exothermic (i.e., the reaction produces heat). Heat increases the rate of propellant decomposition. More importantly, the exothermic nature of the reaction creates a problem if sufficient heat is generated to initiate combustion. Chemical additives, referred to as stabilizers, are added to propellant formulations to react with free nitrogen oxides to prevent their attack on the nitrate esters in the propellant. The stabilizers are scavengers that act rather like sponges, and once they become “saturated” they are no longer able to remove nitrogen oxides from the propellant. Self-heating of the propellant can occur unabated at the “saturation” point without the ameliorating effect of the stabilizer. Once begun, the self-heating may become sufficient to cause auto ignition
    .


    NOx gas is a mix of compounds all of which are reactive. http://en.wikipedia.org/wiki/NOx http://en.wikipedia.org/wiki/Nitrogen_oxide When smokeless propellants break down NOx gas is released. Nitric acid gas is only produced in the presence of water, because it requires a hydronimun ion, but there is plenty of water in air.

    The Armed Forces have stockpile surveillance programs but each Service does theirs a little differently. If you want to see all the different tests the military uses to determine propellant characteristics, look at Mils Std 286 Propellants, Solid: Sampling, Examination and Testing to be found at https://assist.daps.dla.mil/quicksearch/.

    If you look, you will find aging tests. One common test is for powder to be kept at 65 C (150 F) until it fumes. It if fumes within 30 days it is checked for stabilizer or scrapped.

    The Navy expert told me a few ways the Navy samples its powders and propellants. If the powder is outgassing nitric gas (as determined by change of color of methly violet paper in contact with the powder (Methly Violet test, or Talliani test)), the stuff is tested to see how much stabilizer is left. If the amount is less than or equal to 20%, the lot is scrapped.

    Scrapping powders and propellants with this percentage of stabilizer appears to be consistent across all services.

    Pages 5-11 of the 2003 Army Logistics Propellant Management Guide provide the protocols for testing and subsequent actions for their Stockpile Propellant Program. Basically, all propellant lots are tracked. The trigger for investigation is: "When Master Sample Stability Failure Occurs"

    The Navy expert provided 'rules of thumb' concerning when to expect problems with double based and single based propellants. The rules of thumb are: Double based powders and ammunition are scrapped at 20 years, single based 45 years. In his words “These 'rules of thumb' are particularly useful when the protocol fails. The protocol can easily fail when workmanship or good housekeeping measures are not followed during manufacture of propellant and/or rocket motor or during storage of the weapon system components, respectively.”

    For the home reloader, if the powder has turned red, or smells like acid, it is way beyond its safe limits.

    I am of the opinion that the reason this is not discussed in the popular gun press is because if the shooting community knew that powders had a shelf life, it might effect sales. As we all know, gunwriters are shills for the industry and for decades the shills have been reassuring us that as powder gets old, it becomes benign. I cannot see a reason why industry wants you, the shooter, to be picky about old powders and old ammunition. You might not buy, you might have reservations about buying. It is all about profits you know.
     
  12. tightgroup tiger

    tightgroup tiger Member

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    What he said ^^

    OK then! Maybe I'll look at my oldest cans of double base and reconsider their viability. Although mine have been cool and dry for their entire life.
     
  13. blarby

    blarby Member

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    Sounds like if you had a dessicant availability, in a non O environment, you could store powder for a really long time.
     
  14. orionengnr

    orionengnr Member

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    When I started handloading about 4-5 years ago, I did a bunch of research on the loads/cartridges I intended to start with (.38 Spl and .45acp) and decided on W231 as a starting powder.

    I have not had occasion to regret that choice...but, in the intervening years, I have started to load other cartridges, and have wanted to try other powders.

    As a result, I have bought a fair bit of powder at gun shows...often as not, a can that is 2/3 full of a powder I wanted to try. I always open the container and have a look and a sniff. Haven't found one that looks or smells bad yet. I often get these for $5-10 each, or less if buying several.

    I generally load for target practice...conservative loads. No regrets so far.
     
  15. gamestalker

    gamestalker member

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    When powder goes bad it will start to develope an acidic smell and makes your eyes burn. As for shelf life, if it is properly stored and not exposed extreme cold or heat for extended periods, and kept in a dry climate it can last for many years. I have used IMR-4350 that was more than 40 years old and was just fine.

    GS
     
  16. erikk8829

    erikk8829 Member

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    Just finished up a 8 lb keg of WW 571 that I bought in early 60's $34.95! Been stored from Massachusetts to FL hot, cold damp whatever still shoots fine after all those years, sorry it has been discontinued. Bought originally for 12 ga mini mag 2 3/4 loads for ducks & ended up loading 45 's
     
    Last edited: Dec 7, 2012
  17. shell70634

    shell70634 Member

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    Gunpowder will last a very long time when stored at 70 degrees F. At 170 degrees F in may self destruct in a year. This is what I've been told.
     
  18. TheCracker

    TheCracker Member

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    I was given some powder from the mid 80's a couple years ago that had sat out in a screened in porch. Two were 1 lb cans that were metal and one 4lb can was cardboard.

    I've shot both 1 ponders up and a bit of the 4 lb green dot up with no problems. It wasn't even stored properly! I just dumped a little out to see if it smelled bad and was clumpy to check it, and it wasn't.
     
  19. Jaxondog

    Jaxondog Member

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    Fresh powder has a nice pharmacutical smell to it. You will know when it is bad, it will smell horrible, will clump, and some will turn yellowish green.
     
  20. Slamfire

    Slamfire Member

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    As for storage life at elevated temperatures

    Look at section

    7.3 Climatic impact on the degradation of explosives

    Surveillance and in-service proof - the United Nations

    http://www.un.org/disarmament/conva...20-Surveillance_and_In-Service Proof(V.1).pdf

    Gunpowder is a high energy substance that breaks down to form a low energy substance. When it breaks down it heats up and occasionally ammo dumps go Kaboom!. Just google that and see how many ammunition dumps have blown in the last couple of years.
     
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