Quite correct Graeme.
I think the scope you used was one I'd just purchased --- but I could be wrong.
Anyway I've just dug my Tornado out of the gun cupboard and taken a squint at it --- I didn't realise how much work I'd done to it until I read an old thread on here last night.
Internally mine is fielding a 26mm Weihrauch piston seal, Weihrauch HW95 Spring guide and a HW99 (?) spring, but it seems I gave up on it when I couldn't get past 530fps.
I may have to have another go at tuning this weapon of mass destruction.
All the best Mick