The inner spring guide is a decent length but is hollow and quite a loose fit in the spring. Where the spring goes into the piston there’s an outer thin metal tube with a thin flange at the piston end. There’s no top hat and the spring sits on a raised piece which is built into the piston. ( I’ll do a picture !! )
I’ve got some ptfe rod so I can make a top hat but it won’t be as straight forward as normal because of the outer metal sheath and the shape of the inside end of the piston.
Yes, I’m replacing both the piston seal and the breech seal ( which doesn’t seem to be available on the chambers site ? )but checking back through old threads it’s a rubber O ring 8.5mm OD with 2.5mm wall thickness, and I’ve got two big boxes of O rings so hopefully I can find the right one.
I still can’t get my head around the complete lack of even the tiniest bit of grease, especially on the spring ! I was looking at it again last night and it’s like it’s been cleaned in solvent then never degreased