I'm speaking from a position of almost total ignorance here, but surely a bullet is travelling 2 or 3 times faster than sound? Over the short distances involved is it really possible to do this?
I would have thought a light or electric trigger would be better. e.g. fit the trigger or the hammer of the gun with an electrical gizmo to fire the flash.
A couple of years ago I started working on plans to build an electronic flash trigger which could be light or sound triggered, with a presettable delay before firing the flash. I decided it was too much effort just to satisfy my curiosity so I shelved it before actually building anything.
I guess that if you're firing a gun then the triggering sound would be the gun itself, rather than the sound of the bullet hitting the target. Otherwise you'd have to muffle the muzzle :)
Another way to do it would be to have the bullet break a laser beam on its way to the target, with an electronic delay to firing the flash (as I envisaged for my design).
Cheers,
- Dave
http://www.digistar.com/~dmann/
