Rocketman, I think we're now down to "Dancing with the Stars"--but with angels on the head of a pin. Example: standard 16ga frame size for the old Parkers was #1, but you could also get a 16ga built on an 0 frame, which was the standard frame size for a 20. Could you get a 20 on an 00 frame? Parker experts may know the answer to that one, but guess I haven't heard of a 20 on an 00 frame.

Whatever, the reason a Merkel 1620 is lighter than a standard Merkel 16 (47E/147E) is the fact that they use the standard 20ga frame. You'd have to talk to them about what they call it.