crosman shockwave 22

at 10 yards you really wont need heavier pellets as the retained energy has practically 0% loss plus at 10 yards a head shot should be pretty ez and you'll only need 12fpe of energy witch your riffle is more then putting out now if your really not sure you could always try the jsb 18 grain they drop it most likely at that range even with a decent body shot and of course there's always the fact of its not always weight but pellet type like using a good hallow point over a dome i like H&N Terminator Pellets, .22 Cal, 16.36 Grains for my prod as a back up to my pred polymags
 
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.