This patent for great many
impractical features, frailty and apparent lack of usefulness.
Although six c1aims were granted by the patent office, at least five
of them had been anticipated by other patents as much as thirty years
previously. The outstanding feature of the patent was not even patented.
This was the cartridge used, a semi-self-contained metallic round. As
Hall himself expressed it, "the percussion-primers of peculiar construction,
which are employed with the cartridges with which I propose to load the arm"
were made by attaching a tubular percussion cap loosely to the base of the
cartridges. The exploded percussion tube remained in the cylinder after the
cartridge was fired. The bullet shield on the front of the cylinder dropped
down so that the chambers could be loaded. The hammer was almost entirely
enclosed; only the hammer spur protruded.