Technically gas is "soft" but doesn't seem that way when powder explodes. It doesn't seem trivial to contain this energy - the vessel would still explode, give

Technically gas is "soft" but doesn't seem that way when powder explodes. It doesn't seem trivial to contain this energy - the vessel would still explode, given enough energy in the wheel? Certainly safer than launching a giant death Frisbee... But lots of energy is still lots of energy. I guess it's a bit machine gun bullet vs hand grenade - about equal energy - but the grenade will just blow up a room while the bullet will go through walls and lodge in an engine block.