We all seen mistakes in movies when it come to guns, silenced revolvers; Luger pistol goes click, click, because a dud round; Winchester model 94 appears in a western during 1870s...etc. These day most movie gun are special prop guns made to only fire blanks, while blank cartridges like the old 5 in 1 are used for manually operated firearm like revolvers; lever action rifles and the like, to make semi/full auto firearm to cycle with blanks is not a easy task, not to mention it has to look realistic and above all safe while being use. Here is a video from the Forgotten Weapon site about a movie gun rental company, and some of the modification they made to movie guns, it's a bit long but very informative:
Charlie Taylor Interview: Blank Fire Guns for the Movies – Forgotten Weapons
Charlie Taylor Interview: Blank Fire Guns for the Movies – Forgotten Weapons
