This is put out here for risk assessment. You really have to look at what you have and make your own decisions.
I have access to a gentleman who is an energetics expert. I asked him about smokeless powder lifetime. The whole topic is a subset of “Insensitive Munitions”. A term you can Google and find bits and pieces in the public domain.
Smokeless propellants are used in more applications that just cartridges. Rocket motors, explosive warheads, these all use smokeless propellants.
He told me that powder starts deteriorating the day it leaves the powder mill. The rate of deterioration of double based powders is governed by the Arrhenius equation.
http://en.wikipedia.org/wiki/Arrhenius_equation. Single based powders apparently deteriorate in a linear fashion.
What the expert told me was that double base powders are made of nitroglycerine (NG) and nitrocellulose (NC). The NG wants to wick its way, through capillary action, into the NC. Forming a lower energy state compound. In the process of combination nitric acid gas is released. As nature wants to go to a lower energy state, this reaction is inevitable. There are stabilizers in the powder which eat up the nitric acid. The stabilizers get consumed over time.
Exposing powder to high temperatures for extended periods of time is bad. Heat accelerates the reduction-oxidation process.
Cool dry storage conditions, he actually said “artic”, are about the best for long term storage of powder.
The expert said that Navy powders are initially tested at 10 years. They put a litmus paper in contact with the powder. If the paper changes color, nitric gas is present.
If the paper shows a problem, they then chemically test the powder for the amount of stabilizer in the powder. If that drops below 20% original, than the powder is scrapped. You have to have the original powder records to know how much stabilizer was in the powder when it was made.
The Army scraps by clock time. Double based powders are scrapped at 20 years, single based 45 years.
A few years ago TALON released tons of demilled military powders. That stuff was at the end of its service life. Half of my surplus 4895 powders went bad. One keg turned red and was outgassing and it was poured out on the lawn. About 8 pounds did not turn red, but went bad in the case. First indications that I had a problem were that loaded cartridges started having a lot of split case necks on firing. Then case necks started to crack on the loaded ammunition. When I pulled bullets, I smelt nothing, in the case or in the bottle, but I found green corrosion on the bottom of bullets. I believe that nitric acid was weakening the work hardened areas of the case, and causing corrosion on the bottom of the bullets.
Before pouring it out, I shot the stuff in Highpower matches. It actually shot very well but I had unusual retorts. Some load, some not so loud. The expert told me that pouring it out was the right thing because the retorts were indications that the powder was not burning consistently. Could have had a pressure spike.
If the powder changes color, it is bad. It is grossly bad. It was bad a long time before the color changed. And it is time to pour it out. That is when you typically see red rust in a metal powder can (acid gas eating the can up) and red powder.
Older powder, such as yours, has got to be at the end of its shelf life. I shot up cans of old Red Dot and Bullseye and did not have a problem. Does not mean you won't have a problem.
I was told that when enough nitric acid is released, the powder will spontaneously combust. The chemical reaction produces heat. He diagramed the chemical reaction and hot spots can develop as energy is released. As the Military is extremely scandal sensitive, they won’t tell anyone that big bunkers have blown up, but they have. Ammunition depots go Kaboom all the time due to old ammunition spontaneously combusting. You can Google this and find incident reports in the literature. But you won’t find mention of some of the American ammunition incidents that this guy investigated and wrote reports about. We Googled one and found nothing in the public domain.
Water is bad for smokeless gun powders as it damages the powder surface and wicks NG to the surface. Even though the reduction-oxidation reaction is reducing the total energy content of the powder , wicking NG to the surface will increase initial burn rate of the propellant, which has lead to pressure spikes.
Contact with rust is bad for powders. As I understand it contact with iron oxide increased the rate of the reduction-oxidation reaction. If you have dusty red rust in your can, dump the powder. Period.
The Navy used to store cannon powder in pools but the powder was to be recycled. I guess the water absorbed the nitric acid and kept everything cool, preventing heat build up. But the expert told me that the dry lifetime of powder is rapidly reduced after exposure to water.
Attached is chronograph data with Bullseye of different ages. Based on containers, I guessed that one can was made in the 80's, the metal can was probably 60's/70's.
I have totally loaded up the older powders and shooting them as quickly as possible.
Code:
Kimber Custom Classic
230 gr LRN Valiant 4.5 grs Bullseye lot BE532 (80's mfgr) Mixed Brass WLP (brass)
16-May-09 high 83 °F OAL 1.250" taper crimp .469"
Ave Vel = 782.7
Std Dev = 13.41
ES = 52.05
High = 815.5
Low = 763.4
N = 28
230 gr LRN Valiant 4.5 grs Bullseye 99' & 2005 mixed lot Mixed Brass WLP (brass)
16-May-09 high 83 °F OAL 1.250" taper crimp .469"
Ave Vel = 805.2
Std Dev = 38.07
ES = 136.9
High = 912.4
Low = 775.5
N = 24
230 gr LRN Valiant 4.5 grs Bullseye lot 827 (60's/70's powder) Mixed Brass WLP (brass)
16-May-09 high 83 °F OAL 1.250" taper crimp .469"
Ave Vel = 822.9
Std Dev = 14.14
ES = 55.24
High = 853.7
Low = 798.4
N = 26