Thanks for the good advice lads. I learned a long time ago that brute force and ignorance are incompatible with delicate engineering! I can see from the drawing how the spring compressor plays it's part with the caps, so I will go easy. My concern is having the correct spacers for the end cap to get the timing set up correctly. I see Gotha sells the spacers, but I'd like to hear what you guys have used to get it set perfectly.

There's a couple of diopters on druckluftwaffenonline just now for about 80 euro... I'll keep an eye on egun as well.

Hopefully I'll see the gun this afternoon and get my name on it. I only applied for my air weapon license yesterday, so unfortunately I can't acquire until I get it back. Hopefully, the gun will be in my hands within a couple months at the latest. Good wee winter project.