A mult-shot revolving tear gas launcher developed in the 1930’s. There were different models with different bore sizes, ranging from 12 gauge (not shotgun shells), 26.5mm and 37mm. It never really caught on and all of the tools and machines used to make it were destroyed.
The one above is a 37mm launcher but because it was made in the 1930’s, it cannot safely handle most modern day high pressure flare or gas rounds. To be honest I’m not sure what that thing at the top is. I’ve seen these with a scope and some without but whatever that thing is on top, it has a bolt handle. The launcher’s trigger is visible on the rearward pistol grip.