This seized .22lr improvised hand was made by modifying a staple gun, like you would use for upholstery, with a bent piece of sheet metal. The common but unofficial explanation I found for this was it was made in a prison.
I recall a movie where some kids were menacing another kid with a bullet braced in a vice while they were waving a hammer over a nail placed opposite the business end of the cartridge. Life, uh, finds a way?