I've only shot it at 100 yards and it easily shoots better than I can hold it.
The barrel was made by Phil Quaglino. It is a .40 caliber with a 1:18 twist, the rifling being about .003 deep.
The bullets are swaged paper patch style without grease grooves but with a hollow base.
I patch them with .0015 thick dress pattern paper and lube them right before they are loaded into the gun with a 50%/50% bees wax/Vasoline mixture.
The upper box bullets are 300 grain and the lower box bullets are 400 grain.
I load these over a 70 grain load of 2Fg powder.
Because of the butt's hook I had to also build a carpet covered 4x4 to support the gun while loading.