Q: I have been given three unopened cans of AR2209 powder. that had been stored for over 20 years. I would like to know if this powder would be as good as new powder, or if it would have deteriorated? How long can powder be stored in its original container without losing some of its power?
Geoff Mc Call
A: I am unable to give a definite answer on this, because there is one unknown factor. Under what conditions has the powder been stored for two decades? With proper storage, the shelf life of modern smokeless powders is practically indefinite. But if exposed to heat or light it can deteriorate in just a few months. Your powder is in unopened original cans so its hasn’t had light exposure. If you can determine if it was previously kept in a relatively dry, cool place, then it will likely be as good as powder of more recent manaufacture. If on the other hand it was kept in someone’s garage or garden shed through many hot summers, it will probably have badly deteriorated or at least lost some performance factors. I keep all of my powder in old deep freezers where it is insulated against temperature changes. I have Du Pont powder that is probably over 30 years old and still in good condition. However, I wouldn’t guarantee that it hasn’t lost some of its punch.