I read most of the advice on how to check to see if your powder is good. Seems like the smell test is what everyone subscribes to.(that applies to a lot of things in life) I have smelled the powder, and I don"t know that I can say it smells like solvent or acid, as I dont know what acid smells like. It doesn't have a strong odor either way.I have smelled it several times, long inhalations even, and it isn't painfull. Also, I burned some yesterday on the garage floor. Can you tell anything from doing that? So based on that, do you think my powder is still good. I hope so, because I can't stand the thought of dumping out 16#'s of powder.
That is a very good question. And there is not an easy answer unless the powder has gross indications of going bad.
The gross indications are the bitter smell due to NOx, red powder granules, fuming gas emissions, others have said “red gas”. By the time you see these the powder went bad a long time before.
Half of all the surplus IMR 4895 I purchased went bad.
The first 16 lbs, I used up eight pounds quickly. For whatever reason, I pulled the bullets on some of that stuff and found green corrosion on the bases of the bullets.
Similar to these pull down bullets from old US ammunition. Not the horrible one, but the ones with the small green spots.
I don't remember what US ammunition these came off, I pulled them decades ago, might have been WWII ammunition that came back from China.
The last eight pounds, it sat around. When I opened the bottle top, it smelled bitter. Red dust flew around.
I gave it to a machine gunner guy. He put it in the laundry room. Passing by the laundry room he tossed soiled shorts at the hamper, but missed. The short ended up on top of the powder bottle. Overnight, acid gas from the bottle ate holes in the shorts!!
This freaked my friend and he poured the stuff out over his lawn.
Since then I have had more surplus 4895 powder from a different vendor go bad in the case. Green corrosion on the bottom of the bullets and cracked case necks.
This powder never smelt bitter at all. I shot this powder in highpower matches and it shot exceptionally well, but case necks cracked after firing. I also received “funny” retorts and the occasional sticky extraction. The longer the ammunition sat around the more cases necks would split when fired. In time virtually all of the remaining 700 loaded cases experienced cracked case necks without the stresses of firing.
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 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.
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 a main offender because it is always in air.
Because water reacts in a negative way with smokeless propellants, quality ammunition is manufactured in humidity controlled environments. Between 40% and 20% humidity. They don't go lower due to electro static discharge concerns.
The best storage condition for powders is arctic. Cold and dry.
When smokeless propellants break down NOx gas is released.
http://en.wikipedia.org/wiki/NOx http://en.wikipedia.org/wiki/Nitrogen_oxide “Oxides of Nitrogen” all of which react and cause corrosion. Nitric acid gas is only produced in the presence of water. Requires a hydronimun ion.
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. In retrospect, this explains the “funny” retorts I experienced and the sticking cases. It is an extremely rare occurrence, but old ammunition has caused rifle Kabooms.
The Armed Forces have stockpile surveillance programs but each Service does theirs differently. If you want to see all the different tests the military has, look at Mils Std 286 Propellants, Solid: Sampling, Examination and Testing to be found at
https://assist.daps.dla.mil/quicksearch/. Scrapping millions of dollars of propellant is not something that is taken lightly, however keeping the stuff to the point it auto combusts and costs hundreds of millions, if not billions of dollars of damage is unwise.
The military does not talk about this, but bunkers and ammunition storage areas have gone Kaboom due to old powder. That nitric acid builds up, creates heat, and the stuff blows up. It blows up inside the case or the shell.
http://www.liveleak.com/view?i=13c_1205681217
The Navy expert told me the Navy samples its powders and propellants. If the powder is outgassing nitric gas (as determined by methy violet paper that changes color (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.
The Army has surveillance programs, based on the attached links below the Army is testing powders, but what I don’t know. I was told the Army scraps small arms powders by time. Double based powders and ammunition are scrapped at 20 years, single based 45 years. These shelf life dates may apply to a subset of ammunition as I am aware of units being issued WWII 50 BMG for practice purposes. Reports from the users were that the stuff did not function 100%.
The expert suggested that it is likely that surplus military powders are not on the market anymore due to liability issues. The stuff was scrapped because the military decided it was not safe to keep around anymore.
If the powder has turned red, or smells like acid, it is way beyond its safe limits.
This powder is from a FA 11-1898 30-40 Krag cartridge. Obviously it is bad.
I sent the IM expert the link with this Garand blowup,
http://www.socnet.com/showthread.php?p=1344088
and the pictures of my corroded bullets and pulled Krag red powder, and this is what he wrote back:
Wow
The red color indicates that the stabilizer is depleted and the redox reaction is degrading the nitrate ester. (I assume this is a single base gun propellant, and the nitrate ester is NC.) Please dispose of this powder and ammo supply before it starts to get warm or self-heat (via autocatalytic exothermic reaction). This stuff can be a runaway reaction and spotaneously explode in storage.
The cracked case necks are proof that the outgassing of NOx is occurring. The pressure build-up is evidently enough to fatigue the metal at a high stress location in the cartridge case (@ the neck bend). You should also see a bulge in the cartridge base (where the firing pin would strike b/c there is a circular joint crimp there between the two metals). This ammo would explosively vent at the crack if you tried to fire it in a gun. Just like the Garand example you sent. Please discard this ammo.
The corroded ammo is the same as above (redox reaction gassing NOx) except this stuff actually got wet too. Water provides a medium for corrosive acid reactions to result. Please discard this ammo.
Lessons learned -
(1) Ammo has a finite shelf life
(2) Ammo can be dangerous
More to read if you wish:
www.dtic.mil/dticasd/sbir/sbir031/n154.doc
This paper discusses most of what I have written, but it has a confusing, almost contradictory section where it states that “Suddenly, propellant that has spent its entire life in a configuration that was considered inherently safe from the risk of autoignition is now bulk packaged and stored in a concentrated mass that may be sufficient to allow autoignition to occur.” I don’t understand how it can be considered inherently safe if it is old enough to be considered an “unstable propellant” and cause auto ignition if decanted. Maybe something was removed in editing and the text got garbled in the translation. Still, it is an interesting read.
http://www.almc.army.mil/alog/issues/JulAug08/propellant_stab_eq.html
