If shooting at the higher OPEN or the HUNTER allowed 20 fpe limit .... the FWB P70's needs to have an *aftermarket PLENUM / breech block extension fitted.
*these are no longer being made or offered best i know. They allowed BOTH scope rings to secure upon the main chassis of the rifle and not 50/50 being one on receiver, one on barrel as the factory 10M configuration did. Obviously offering greater plenum volume and power above 10M requirements,