We had a day off from school, and what better way to enjoy time off than to blow stuff up? The first was filled with bp and just buried. The second had powder taken from some .22 ammo we found on a hike. I knew that unless confined very well, it burns slower than black powder, but I wanted to try it. I took the powder from all the .22s I had (about 30) and put them in a cob. It only filled it about half way. I taped it to a Matchbox truck to blow it up. The explosion was just a "pop!" and it seemed to have just shot out the top, but after digging it up we saw it did rupture and destroy the toy car.

Casing of the first cob

2nd cob taped to toy car

The recovered pieces

The casing

For the next cob, we found an old, broken clock to use it on.