A client brought in his old Webley Senior pistol this afternoon, his main concern is lack of power. Its a 5.5mm model.
I tested it myself with a 5.52 AA pellet, pellet sits in the crown basically after the shot.
I opened her up to look at the piston seal, a copper seal with a thin plastic shim underneath serves as a piston-seal.
I wonder if I shim the copper seal up with some special shim material that I found one day for such a rainy day, if it would help?
The breech-seal is also missing but that was sorted with a o-ring. From what I read on the internet the loss of the breech-seal is quite common.
Any advice from someone?