The Klingon Death Sting is an interesting weapon, as it was seen before, in the middle of, and after the development of the other type of Klingon Disruptor. That type, which we all recognize as THE Klingon Disruptor of the DS9 era was first seen in Star Trek III. It was later changed to have a "beakie" nose in TNG and later.
We first see the Death Sting in Star Trek: TMP, but not really! It is actually stuck in its holster and we only see the butt sticking out of the first officer's holster.
|ST III Klingon Disruptor - note the nose|
In Star Trek VI, we are back to the Death Sting, but now it is a different color and the actual prop is cast off a TMP version. It now has a solid back.
TNG starts off with all Klingons using the Death Sting.
|In the TNG episode "The Icarus Factor" we see 8 Klingons with Death Stings in their Holsters|
|The Emissary - K'Ehleyr has a Death Sting in her holster|
|"Sins of the Father" - Note Kurn's holster|
However, in "Redemption Part I, Klingons have switched to the Beakie Disruptor.
|"Redemption Part I" - Note the silhouette on the right|
|"The Chase" - The Beakie is in full force!|
|"Firstborn" - We see the full beak!|
The Beakie was developed because the Star Trek III style kept breaking when actors pulled it from the holster.
And then Deep Space Nine kept the Beakie Disruptor from the outset.