This isn't a car "thing" but it's still a slight goof I noticed while watching Lethal Weapon 3 recently:
In the movie, Mel Gibson takes Danny Glover's vest and sets it up at the gun range, he loads a single "armor-piercing" round into the handgun, then after he shoots the vest he cycles the handgun's slide.
If he didn't have a magazine in the handgun (which is the most likely scenario and would make sense, since he's loading a single round) the slide wouldn't automatically lock back, but the gun would be empty after he fires, so cycling the slide back and forth would be pointless.
If he had an empty magazine in the gun, the slide would lock back after firing, the gun would be empty, and the motion he makes in the movie would not do anything useful either.
If he had a loaded magazine in the gun, then he would have created a strange malfunction when he manually chambered the "armor-piercing" round, because when he released the slide the natural function of the handgun would have been to try and load the first round in the magazine.
My theory is that the first scenario is what happened, and Mel Gibson simply locked the slide back after he fired the shot to indicate a "safe" gun but during editing they added in a sound effect for the sake of having a sound effect. I
what they were going for, but it made me scratch my head for a moment...
