I'll take the correction. So, BP is not unstable w/ age.
We had been trained not to handle the things, secure the area and call the local bomb squad. Pretty basic. I made the mental jump that they were delicate/unstable.
The inertial fuse, or a percussion fuse. The detonation rate for the rifled guns w/ percussion fuses was much higher. More reliable system, and the rifled projectiles are stabilized (not stable again!) and land near nose first. BANG. Because of the smaller bore, the explosive effect was much less.
Could a percussion fuse be unstable???