I received the barrel, and as James noted, the vent is too low, perhaps by 3/16". I intend to tap the hole and blank it with a screw. It is a rather neat piece of hardware, but has some marks and dings from years of storage and handling. The muzzle needs some cleanup and crowning as it is squared with saw marks on it still, and the breechplug is not set to a shoulder, but has a very fine thread of slightly above bore size. Not exactly what I would like to see, but it has been proofed (Belgium, not London BTW) and a pistol does not carry a heavy charge anyway. The bore measures .570". I intend to pair it with a Chambers Queen Anne lock. Should make for an interesting project.