It appeared as a part of a big scanning device in TOS: 'Metamorphosis' and 'The Ultimate Computer'.Īnother Gatherer in TNG: 'The Vengeance Factor' carries a different kind of rifle. Even the original ribbed 'barrel' of the Eminiaran weapon was re-used. Aside from that, the Romulans used this type of disruptor too, in 'The Enterprise Incident' where they had Klingon ships likewise. It was later modified to serve as the Klingon disruptor in TOS: 'Friday's Child' and 'Day of the Dove'.
The disruptor which is nowadays familiar as a Klingon weapon began its life on Eminiar VII in TOS: 'A Taste of Armageddon'.
Certainly we are not supposed to watch closely enough to notice that distant civilizations have the same weapons. There is no need to seek for explanations. Please note that every statement made here should be taken with a grain of salt. Here are quite a few examples of beam weapons. Many props of Star Trek were later modified or even recycled without changes to represent equipment for a different purpose or of another civilization.