The Japanese have made very good ones for years. Makers include Marushin/Maruzen and MGC. Very collectible in the US. Most are made of high-grade plastic, but I think some are made of zamac or similar non-pressure-bearing metal.
They are specifically designed so that live ammunition cannot be inserted into the chamber, and they cannot be drilled out or fitted with real firearm parts to fire live ammo.
Do they look EXACTLY like real guns? Are bullets visible in the cylinder of a revolver? Can you load a round into one for a scene where the good guy is reloading to shoot back at the guy wearing the black hat? If not then I would think they would have limited use in the film industry, which was the context of my question.
Aren’t those airsoft guns?