The Girandoni repeating rifle may be most famously known in America for its role in the Lewis and Clark expedition of 1804 where the notion of having a gun that didn’t require powder, a limited commodity in the uncharted territory, had a lot of appeal.
This video not only goes into how this early and very powerful air rifle works, it touches a bit on its history as a service rifle with the Austrian army.
Dr. Robert D. Beeman has the gun’s history well-detailed in this complete summary, including a little about how powerful these guns really were.
While early accounts estimate the Girandoni made a bit over 100 foot-pounds of force at the muzzle with its .46-caliber ball, later theories about how much pressure these tanks were capable of withstanding put the muzzle energy at over 300 foot-pounds (up to around 500 foot-pounds in one sorta out there estimate), meaning that this air rifle was easily as powerful as many cartridge guns that wouldn’t be invented for another century.
Unfortunately the complexity of the design and the limited training given to the majority of its Austrian military users would be the rifle’s downfall. They were neglected and failed in large numbers and would eventually be replaced by common black powder rifles.