Since we are only talking theory here, I theoretically believe I saw one of these in action – up close and personal - in college. I believe – theoretical again - these were called tennis ball cannons. Guess why. <img src="images/graemlins/smile.gif" alt="" />

Details may be sketchy at my age, but I believe Old Milwaukee cans were involved in the manufacture of said test tube. The propellant was regular liquid lighter fluid. The kind you use for a Zippo. A small squirt was added to the firing chamber, the tube was aggitated to vaporize the fluid, a tennis ball was dropped into the tube and flame applied to the touchhole. I have heard the tennis ball would clear a three-story building. Again, theoretically..

No ATF were seen during the testing of this device.

Theoretically, have a nice day. <img src="images/graemlins/grin.gif" alt="" />