I have to agree w/ Rod. I have never heard of a revolver giving better velocity with the same barrel length and round than a single shot. If you don't think much is lost in the barrel/cylinder gap of a revolver, go out wearing a pair of shorts, sit down, rest the barrel of the revolver between your knees w/ the front of the cylinder against your knees and pull the trigger. You will burn your skin good from that "little" bit of exchange. Pressure is lost there. This won't happen w/ a single shot. This may not be significant to some, but it certainly doesn't help ballistics.