SpudFiles

i was watching in youtube until i found this
good release mechanism

[youtube][/youtube]

Not that good of a "release"...it could probably never hit something moving.

In Firearms a "hang fire" occurs if there's no discharge with in milliseconds.

Looks like he prefilled it a little and used a low pressure hose to burst it(?).

A tyre filler would probably work faster. Higher pressure would probably shoot the marble faster with a thicker burst-disc also.

I Was designing something similar with (2) 6" brass nipples(Derringer ) that would work better, but saw the brass fitting and started on a high pressure Blow-forward-bolt instead.

Still a cool vid. Maybe a Propane (pressure source) through a pistol grip (sand blaster or power tool handle) into a different chamber that's prefilled with a larger barrel would probably be more impressive.
It could have a ball valve, and two large diameter barrels too.

If a glass burst material is used it has added benefit of flying out behind the shot load. 8)

Vid demonstrates the power even of a weak burst-disc is all.