Thanks, that was part of the problem, I found some places that had special guns, a lot of information on how to make the effects like the squibs to simulate target hits, and even one site that looked like a lot of good info until I realised it was people posting about a video game...
I know I have seen non CGI ( although I did watch one the other day where the belt fed machine gun was tossing shells and fire, but the belt was not moving
)
Of the non CGI flavor though, what I do not know is if those were special effects guns shooting special ammo or real guns shooting special effects ammo, and if so what effect would that have on the gun itself.
I am filing this under my no practical purpose, just fun, so all the *shooting blanks* and *wasting time* etc... Yeah I get that, not the point of the question, note I did not ask which style blank is better to kill zombies...
Assuming it has some sort of chemical burning slower than the powder, and probably adjusted to make it more bright or visible, I could see anything from iron oxide to phosphorus being used, and that would likely lead to a much dirtier cleanup, but would it cause damage?
I figured someone here had crossed that bridge and would have some experience to share.