17 February 2020
I inherited three cans of IMR 4320 that was packaged in 1991 (E91 / OC 9 / L5158). They were perfect on the outside and still factory sealed. When I opened the first can, fine rust dust came out. The odor was not of decomposing nitrocellulose, like Urea or nitrate salts, but very like diethyl ether. All three cans were the same inside.
So, I cut a can open and found rust on the inside of the can where the powder had laid next to the coating on the steel. It was heavier at the bottom of the can. The powder appeared normal except for the coating of rust and no coating or graphite on the kernels.
I was able to separate the rust out by trickling it down a slope with a 40 pound rare earth magnet under it.
The kernels measure .017” long and .014” thick. This is nowhere near specifications for DuPont IMR 4320: .042” by .034”. In fact, I cannot find any IMR powder that has kernels that small.
Then I checked to see if there was some sort of chemical decomposition going one. If there were one of the main products would be NO2 or NO3 as vapor. Using litmus paper, there is nothing going on. Everything is pH-7 even with keeping the kernels damp for 48 hours.
Therefore, I don’t think it is powder going bad, but something palmed off to reloaders that dissolved the liner of the can.
However, I would never shoot this stuff and it is not what is on the label.