transfer/valve porting, and hammer energy.... My apologies, I was not even aware there was a sub-12FPE version for the UK.... If that is the case, then perhaps someone from the UK could provide the information.... It would certainly be possible to strangle one down that far, the .22 cal Hatsan AT-44 is hogtied all the way down to 7 FPE from 30 FPE for the Canadian market just by restricting the airflow....
