What makes a shell not go high enough?

[lcwallis]

Quite a few years ago we shot some different shells (black mamba, big chief, I don't remember what else ...)
Some of the shells got mixed up and I think big chief (smaller shell) was put in black mamba tubes. The shells only went about 20 feet in the air.

I'm guessing the tube diameter was too big? is this correct or would it have something to do with how long the tube was?


Thanks

[Bazerk]

Tube was too big and there wasnt enough back pressure to put it up as high as it should have gone.