Don't even think about it!
Dave Welham of Air Masters 88 did one and will not attempt another. The break down isn,t that hard but the fiddling to put it together and function correctly is.
Dave Brayfield at Staffordshire custom rifles did my servicing and at a good price(he loves them).
Sports Match are good but expensive,however if you insist on fiddling with one and going inside I have a drawing I made of the section internals if you really want the aggro.
The main problem is the balance of the bleed valve? and second cup spring resistance. Either too much or less movement will close the supply of air or leave chamber open to main reservoir. Less power or more!.There is a gauge to measure this I believe?
PM me Holly if you want a copy of drawing, call Dave Welham or Dave Brayfield who I am sure will educate you to the niceties of John Fords design.
HERX77
And mine shoots really good save you asking .