Benji HB22 tune?

Hey guys. Is there anything that can be done to tune up a Benjamin HB22 for either velocity or accuracy, and if so, who would do it?

Anything much I could do myself to help it out?

By the way, I sure appreciate the advice I got here concerning my 953. It's standing proud right beside the Beeman and the Gamo now. Tack driver.

Thanks,
Parks