I made some change in the checkpiece to improve accuracy.
Yesterday I receive a Lothar Walter Poligonal barrell and went immediately to the torn to machine it.
Now I have a rifle that is shorter than 39", super comfortable and super accurate at the long distance (160 yards) I wanted.
It is hard to request something better: comfortable, perfect lenght, a lot of shots per fill and super accurate.
Officially, I am out of the market as PCP's rifles buyer.