You wont know until you try...not all rifles like the same pellet, even from the same mfgr... You need to try different weights and head dia to see what works well in your gun. Stick with popular name brand pellets and you will find one that works. Before serious testing, get a simple tune done first!! You can buy kits or just use the factory parts like I do. My TX200 has a basic tune with factory parts, shoots 900 fps with 8.4 AA pellets, can hold sub one inch groups at 50 yds and one inch at 75 yds when there is no wind. I shot a 12 ft lb version of the TX for over 20 yrs in competition and won many matches with it. I dont have any problems with the slightly higher recoil of my fac rifle but some prefer the 12 fp version....that is something you will need to figure out. Tune, then experiment with different pellets, have fun, it will take a little time!!!!