I have one that rattles along at 11 ft lbs with no dieseling or recoil issues at all and another which is ab absolute pig at about 7 ft lbs - my experience is that they vary wildly but they are capable of good performance at a reasonable power level. Pellet selection is the key - I always buy old british .22 pellets when I get the chance (assuming its a .22)
HTH
"But we have our own dream and our own task. We are with Europe, but not of it. We are linked, but not comprised. We are interested and associated, but not absorbed."
Winston Churchill 1930