The thing about junk like this is it will fire a fairly large blank load or two. That's enough to make someone want to fire a projectile at some point, and that's where the pipe bomb thing comes in.
Being a curious sort, I have made more than a few extreme experiments with things that go boom. Being that I value my hide and hair, I have always taken a lot of precautions as to length of fuse, and what I was hiding behind when the experiments went off.
Not too long ago I fired a golf ball from a fiberglass tube meant for fireworks shells. 1/8 pound of powder with the bottom end pounded into the ground. No problem, golf balls are pretty light, it went out of sight. But the tube was noticably larger in diameter. So next, I pounded the tube back into the ground (it had popped out a little) reloaded with the same charge, and this time used paper wadding and filled the thing with damp sand. Guess what? Tremendous boom, very impressive. There was a hole 1 foot deep and 1-1/2 foot wide where the tube used to be.