Just like to say that I read through lots of tips from this site before attempting to strip down and rebuild my Webley Mk3 (many thanks to all who contributed). the gun had been dry stored under the stairs since the late 1970s with just the odd wipe down and pellet through it every few years but, was seriously underpowered and all the grease had solidified.

I stripped down every moving part, gave the barrel a good pull through and light lube, degreased and cleaned everything before applying new grease and lube, fitted a new spring and PTFE seal which took a little wate with all the wet and dry rubbing but, now moves up and down the cylinder with gentle but firm finger pressure and sounds like a bicycle pump. Put motorcycle chain lube on the new spring to dampen it down while I sealed the loading port barrel with MB grease and ensured a thin smear of gasket sealant went around the edge of the cover plate. With the loading port in the "load" position, working the underlever cocking arm back to the point where it almost engages the trigger, and then letting it go back again will result in a pleasant Pssst once the loading port is flipped back to the firing position, indicatin a good seal.

All in all the gun is now rejuvenated, much more powerful and smooth and was instantly shooting around 2" higher than the scope had previously been set for at 25 yards although it has taken around 100 pellets to start grouping decently as it was obviously bedding in.