Jay, the biggest surprise to me was finding power already wrapped up in the gun, but many assume the internals being inside the grip must be too small to bother with tuning.
The piston is a very short design within the chamber, but it means you can have 2” of stroke which is quite respectful and the diameter of the piston exceeds that of the HW45…This equates to a volume which not only exceeds that of the Webley Tempest, but has an in line Transfer port of barely more than 3/8” which must be quite efficient, compared to having to pass through a 90 degree bend for barrel over cylinder guns
So i knew it had to be more powerful than the 420 fps i was getting.
To improve the power and accuracy, you need to chuck out the duel spring set, as the inner spring behaves as the worst inner guide rod of all time. Utilising a HW30 single spring, with a correctly fitted Delrin guide and top hat. This allows free movement of the spring.
I then sized the TP down to 3mm with a stainless steel tube to increase pressure and reduce slam. We now get zero vibration and no slam, but more importantly at 500 fps+ the pellets are leaving the barrel before the recoil takes place. Finally choosing fast start pellets, such as AA express and its difficult to beat.
I did receive some criticism for modding a classic, one shooter commenting it is sacralidge to alter rare pieces from the world, but my take is that it is my gun and nobody else's and will never be sold on….I have also improved the gun no end.