hello, I have an avenger, not an avenge X, but I often will tune for a heavy pellet (22 cal) like the 25.4 grain jsb, and then just lower my hammer spring tension for something like the 18.1 grain, from my experience it will work, just not as efficient. so using the transfer port adjuster can work, but I would imagine it wouldn't be as good as re tuning the gun. what I do personally is re tune the gun for different pellets, unless im just testing them for accuracy, then ill just mess with the Hammer spring and leave the reg as is. maybe that would be an option? I haven't gotten my hands on an avenge X yet so I don't know how much the transfer port knob will affect power. depending on what pellet you're shooting it might just work regardless of the transfer port knob, like the 18 or 16 grain pellets will most definitely be accurate at say 880 fps, but there's a good chance they would also be accurate at say 700fps. its all just a guessing game until you try it tho.
