Hi Andy,
As Mauders says it started life as a HW95K, but the only thing not changed on it or tuned is the silencer.
Trigger stripped down and rebuilt after polishing and tuning.
Barrel is chemical treated.
Action fully tuned.
Stock changed.
SFS's own spring.
SFS custom made full internals, guides and top hat.
Piston polished and sized to the action inners and some other stuff i dont really understand.
Si.