I have a four bolt Mk 2 prosport and was having a few problems zeroing it the other week so stripped it down for a clean up and service .
I found that the main fixing bolt ( on the trigger ) was causing the problem
and after deciding to use just the four stock fixing bolts the rifle is bang on again . I guess the action will be secure just being held by the four bolts and I will make sure they are kept tight but am just pleased I have found the problem as I really want to use it for HFT .
I just put a 10 shot thumb nail sized group at 25 yards indoors which is promising so I guess its time to practice - shame really as I wanted to use it in the summer but never got around to sorting it out .
Its true though , its so satifying to shoot a springer again thats for sure !