[Sabre9mm]

when you watch a movie, and they fire their weapons, there is always a plume of fire coming from the muzzle.

I have fired hundreds of rounds on video to go back over visually post range.

Aside from my shotgun, I seldom ever see this.
Granted camera speed can affect this, however laws of averages would provide the likelihood that I would not ALWAYS fire between frames would eventually change.

Granted it is easy to CGI in nowadays, but there are definitely movies where this is not the case, so I assume there must be some special blanks that produce this effect.

So where would be the place to get such stuff, and would it harm a normal weapon to run it?

Or anyone know much about it in general?