When you absolutely, positively have to kill every replicant in the room, you have Richard A. Coyle's remarkable recreation of Deckard's gun in Blade Runner. Most of the major pieces are made of metal and it even includes a fancy display stand for impressing skin jobs.
What I have done is to take a hand picked copy of a stunt model and a casting of a real Bulldog 44 Pistol and Styer Model SL of the same year and copied all the detailing to recreate a copy of the film prop model.
Most of them are about $400 or so and there are some all-metal versions for $1,000.
[Ebay via GadgetMadness]