Hi Alistair
The big thing I found out with that exercise was that you could increase the power output of certain guns by reducing the transfer port diameter.
The other classic example of this is the Webley Hawk MK2 --- sleeve the transfer port down and watch the power go up and the recoil come down.
U.K.Neil, kindly gave me a Webley MK3 at the Boinger Bash --- this is next on the list for a reduced transfer port.
All the best Mick