These guns have gone through several evolutionary valve and internal configuration changes, but all are basically built around the Career Infinity .22 platform which limits the power potential. I have experienced a wide variation of factory tune velocities gun to gun with some factory guns failing to reach even 600 fps with round ball ammo. Power tune results can vary according to the model, especially the earliest models with long hammer tube. Here are typical results using round ball ammo from a 3000 psi fill, muzzle 15 feet from the chronograph showing 6 shots more powerful than the factory configuration. Includes trigger job and new seals.
Factory FPS 640 656 659 652 643 630 619
Power Tuned FPS 742 751 743 721 694 674 642 610
Dragon Slayer Power Tune price $275 plus shipping with insurance.