Firing The Thunder Mug on the 4th of July
I loaded the Thunder Mug with about 300 gr. of FFFg Black and 100 gr. of some old Pyrodex R. I wadded the charge with a bunch of Steel Wool and hammered it down tight. It was splendid!
These are captures from a video of it going off.
The Thunder Mug is made from a hydraulic Cylinder with the ends milled off, welded to a base plate with a handle and a fuse hole.