My experience of German produced air rifles is that the power is restricted by the transfer port size. Opening them up allows the spring to be reduced and gives a nice smooth shot cycle without jumping. My HW 95 would not allow me to keep a constant sight picture through the scope, now very steady and I really enjoy shooting it. The HW 35E I just bought was horrible to cock and shoot, I opened the port from barely 3mm to 3.5mm and reduced a lot of coils off the spring. It totally transformed the rifles performance and ease of cocking.
Baz
BE AN INDEPENDENT THINKER, DON'T FOLLOW THE CROWD