18th Century Grenade Launcher - Hand Mortar (1760-70)
Flintlock hand mortars were use for signaling, launching fireworks, and hurling grenades.
They would be operated by two men. One who would insert a lit grenade then duck. The first man ducking would signal to the second man, the shooter, the mortar was ready to fire.
In the event of the mortar not firing when a lit grenade was inserted the operator would throw the device and reel it in by an attached strap.
This particular example pictured is from ~1760 to 1770s but from what I read they came on the scene in the 1600s. But I probably should edit that for clarity.