I also acquired one. Looks very robust.
Mine works but has very low output velocity.
I stripped it down:
Someone used too much grease (some cheap and dirty stuff...)
O-rings were replaced with rubber (NBR most probably) - I do not see any reason to claim they work worse than PUR.
Barrel seal looks ok overall but shrink a bit and fall out of socket. Previous owner used some glue to fix it in place.
I think I located the problem of low energy: it is evidently problem of worn out valve lever - one which is hit with hammer and pushed the valve rod down. It seems to be weak point of this design.
I will remove old greases and use some good stuff instead.
Some questions to you. Hope you will find a minute or two to support:
1. Do you know o-rings size? Appreciate if you can save me some effort to experiment.
2. Any ideas on how to replace barrel white seal? I believe well chosen oring can work well - however it will increase dead volume before the pellet. Not much but still...
3. Any ideas how to fix the valve lever? I know I don't get factory replacement but maybe you know who can make it to order or have some other idea?
My first idea is to drill it through and make M3 or M4 thread for a hardened screw. That would allow for power regulation and future replacement of this element. I would fix the setting with green Loctite. Should work for quite some years. But maybe there are better ideas...
Appreciate all your inputs. It is great nice piece of pistol and really well balanced. Great trigger on top and it would be pity if I cannot bring it back to service.
Best,
Jaroslaw
Webley Lite W-8 + Bushnell Trophy XLT 4-12x40 DOA600
Morini 162E, FWB 90
Walther Lever Action Long, CP99