Screen Used has a Klingon Rifle for sale. At $ 4,999 this is a pretty fair deal. These are incredibly rare and I was lucky to get one from It’s a Wrap.
Made for Star Trek III, these were basically disruptor pistols with an added “stock”. The pistol was an entirely new design from the “Death STing” used in The Motion Picture. This design was used through Star Trek: The Next Generation, Deep Space Nine and Voyager. The only change being the tip, which was constantly breaking, resulting in the “beak nose” version.
You can see it on Screen Used’s website.