Try a different pellet , BSA barrels prefer heaver pellets , one of the best is Daystate heavies JSB heavies 10.3gr both are the same pellet . When I had mine it was running at 11.7 ft/lb .
For a lighter pellet try jsbs 8.44 grin 4.52 - 4.53 , Daystate sovereigns 8.44 , 4.52 are getting some good results as well and these should run at 11.2 -11.3 ft/lb
Don't for get a new gun will take a few hundred and more pellets to run the gun in .
Don't forget to clean the barrel if it new as well , it might have some factory crap in there .