Every gun in a movie has to have metallic click clack noises so you know there’s a gun involved. A gun with no hammer will be drawn and a hammer cocking noise will play. According to movies, guns a made with the tolerances of a fencepost and are all rattly. This is part of my larger complaint about foley in movies. It often sounds very separated from the action on screen. Not always. But sometimes it sounds like the leather and metal sounds of the cool hero character are as loud as the vocals and have perfect clarity.