@hot diggity posted a wry post in the Motivational Posters thread Motivational Poster Thread (warning content) , featuring a handmade underhammer muzzle loader. It sparked my curiosity and I found an interesting You Tube video clip on one man's effort to hand craft an under hammer action from stock materials and home workshop tools. The Underhammer Society: The Screendoor Underhammer, or Why Gun Control Will Never Work.