Smokeless bang? Like a pistol blank but does not emit smoke, Any Tricks? Thanks?

I am needing to make a gun prop for a contest, However I am not allowed to make any smoke.... Help?
Thanks

orksecurity6 years ago
How strictly is "any smoke" being defined? Would they accept a carbide cannon, for example?

Classic radio sound effect for a pistol shot is two blocks of wood hinged at one end so they clap against each other.

And of course these days you could just use a recording....