I like mythbusters

, but this was about the lamest show ever. How STUPID was it to use water heaters for boilers when just a show or two ago you proved how dangerous they are once the safety devices are unhooked. Then you go and unhook them so that you can use them for a purpose they were never designed for, pressure

. Where these certified boilers, were they inspected, hydrotested, ANYTHING? NOOOOooo. How do you know these water HEATERS had welds that would stand up to the pressure you were putting into them, or any pressure at all, without being guina pigs. I mean 120 lbs of steam will make a helluva explosion too.
Also why stop where you did... Were you afraid they were going to blow? Usually you make every effort to prove a myth even if it means stretching it a bit. Why not 4000 rpm. Why not a curved or angled tube to fire the shot better. Why not a longer tube? Larger diameter, lead shot? I think there were many ways to make this myth plausable as a killer.
BTW I own several 1900 steam tractors and go through rigorous training and inspections so that the boilers will be considered safe. I would be happy to provide you with one, adding a certain amount of authenticity and a whole lot of safety. Or better yet, send me the setup and I'll use it on my ranch and let you know what happens.