I am not alone in a consensus of opinions this little pistol should be pretty good at the range you are shooting, bottle tops at this range is a good guide.

Since you are having accuracy issues, try a change in pellet as some barrels can be pellet fussy. Also, clean the barrel and check the muzzle exit for minor damage as it could be clipping on exit.

Both my Tempest has an aggressive twang so maybe try resting it's butt on a cushion to steady the aim. Lastly, I'd let a friend have a go to see if better groups can be had.