Less than 10,000 produced. Caliber .455 semi-automatic.One interesting aspect is that it was used to arm aerial observers early on in WW1 for taking on German observation planes. Size comparison is with a 9mm luger round.

Very nice! You sure don't see them around much any more...

Initially I was put off by the boxy look, but when you pick it up it fits the hand perfectly and points very easily. Extremely accurate and has functioned perfectly. One drawback has been the lack of available ammo, but dies and brass are available.