The Americans seem to use a lot of 177 and 20 at higher power levels . at least they did when i was into FT and the HFT was just starting . I have only owned 20 and 177 at sub 12 so cant say much other than they dropped knock-over targets pretty easyThose .177 pellets must be going supersonic. I didnt think it was viable to go as high as 20ft lb without getting turbulance problems, but it obviously works for your gun.