Now, movie armorers, I understand your dilemma. The director calls for a complicated gunfight scene. Maybe the actor is in a moving vehicle, or many actors are in the same shot. You only need the actor to fire one or two rounds to complete the scene. Obviously, you only want to give the actors the exact number of rounds they need, even if they are blanks. Safety is paramount.
But nothing kills a cool gunfight scene for me in a movie then when a quick cut shows an actor seemingly blowing off rounds as fast as he can, only to notice that after one or more shots the slide to his pistol is actually locked to the rear.
It's not like you have to specially modify the gun to keep it from locking to the rear, in most cases, all you need to do is take a dremel tool to the magazine follower. It's not really that hard! Hollywood, if you need my help, just give me a call. I'll only charge a few hundered k to consult.