I can’t really answer your questions directly, but I’ve been told that the best way to film a gun shot is to have the actors go through the motions, pull the trigger, make it kick back , etc. and then while editing it, add a frame of white. He said this is the best way, just add the sound effect with the white and it looks good. Supposedly, according to him, movies used to do this, and he actually said Alien did. So, there ya go. I have not done this myself, but once you get a gun, yous hould just test it out yourself on anyone. Then edit it real fast and add the white and sound effect and see how that looks. Hope this helps, and good luck! Let me know if this works for you too!