Well with help from a few friends ive been playing with 12 twist Chazsel .222 barrel liners in custom Airforce Condors..Ive finally been getting some okay results with Lee .225 55 grain cast slugs sized to .222 they are performing well in the 920-940 fps range..They will shoot faster but not as well..I have a 9 twist redman barrel liner coming soon.. The only problems ive had with the custom valves of the condors in 22 cal is too much power...I never expected that with a airgun...Im stuck using 22 cal in Pennslyvania for small game...These 55 grains shoot pretty flat 920-940 fps.. I will be hunting squirrels and shooting more will post results..Anyways old boring Airforce Condor with a $68.00 Chazel barrel liner caple of making 100 foot pounds ..