Prop-Gun idea Answered
I don't have that much confidence in getting this to work, but as an idea I thought I'd share it:
I have a concept of a rotating-barrel automatic-chain-gun, that I can do no problem. BUT, to simulate muzzle-flash, I'm thinking of feeding butane/air down the barrels (blow-lamp type device) and igniting it.
Initially, I think of slip-rings or similar and a camera-flash unit for ignition, motor drive on the barrels.