Thread: Old powder wrecked reloading gear.

Originally Posted by ubique

Long story short - the primary energetic ingredient of most modern propellants is Nitrocellulose (NC). All NC undergoes spontaneous and autocatalytic (self-feeding/ self- perpetuating) decomposition, producing a bunch of bad stuff, including Nitric Oxide, which forms Nitric Acid on contact with air/ moisture. My guess would be that the Nitric Acid is what's eating your metal/ protective coatings. That Nitric Acid also further accelerates the breakdown of the NC and in the worst case can cause self-ignition/ combustion. The more moisture and the more heat/ temperature fluctuation, the more exacerbated it would be - so shipping containers and tin garden sheds are not flash for long term storage.

Hi ubique, some also contain Nitroglycerine, same story but worse!