Each time you step-up to a heavier pellet there are benefits such as greater energy retention and less deflection by the wind. However, at 10 yards these benefits are a moot point. Increasing the pellet weight will make your air gun work harder and increase the recoil (Newton's 3rd law). Accuracy is always the most important factor when using an air gun. A head shot with an accurate pellet that weighs less will get the job done. After all, dead is dead. The most accurate pellet with my TX200 is the .22 caliber H&N Baracuda Green, which weighs-in at a scant 12.65 grains. I've taken quarry such as armadillo, ground hog, grey fox, and raccoon with this pellet. An accurate pellet with your air gun is what you need.