Is it safe to smash cannon guns?

Mainly that powder ring is dangerous, but the charge is small, so if there are only a few it's not a problem. But if you put a few boxes of gunpowder ring is more dangerous.

The main components of gunpowder for smashing guns are potassium chlorate and red phosphorus, a strong oxidizer and a reducing agent. The combination of the two is an extremely sensitive and powerful explosive. Go online and search for yourself, how many cases of playing with potassium chlorate and red phosphorus being blown up and killed.

So if a lot of gunpowder ring in the pocket because of the vibration was detonated, the consequences are unimaginable.