How to make model guns with open barrel smoke?

Hi everyone,

I am new to model guns and wanted to know how to make them spark or at least smoke through the barrel.

Many thanks

Depends on what model you have shorter the barrel the more the effect. Marushin caps produce sparks MG caps do not, a bit of oil as a lube on the piston can produce a lot of smoke, magnesium powder in the round can also produce a good flash.
The japanese have a load of ways to get flash but you just cant get any of it outside of Japan, also they do hollow det pins and special rounds to produce more flash but they sell out in Japan fast and are not exported same problem as the caps.