Quote Originally Posted by joffy View Post
It's a TX piston with the mk1 rod
I think that rod will be a way too short - have you mocked it up to check ?
Also I think the piston itself will be too short as well - you'll need a nose extension - the problem IIRC from mine (it was a while ago) was when the piston is on the forwards position, the rear shoulder would have smacked into the cocking shoe. Hence the need to lengthen.
Assume you are using the new style "in the groove" cocking shoe ? Any you know about grinding the HW sear if you want a rotating piston ?

Its a worthwhile project though, you'll end up with a loverly gun.