22 cal. guns should be shooting pellets with weights between 14+ 15 grs.. Lighter & heavier weights can put undue stress on the system. Gas Pistons are more flexable than Springers with these pellet weights. PBA's are noted to be a gimmick and not accurate. The GP's are detuned for accuracy & recoil etc. ( less FPS as opposed to the regular Titan) . The 1st. secret for accuracy is to find the pellet that your gun likes. 600- 800 fps. is plenty for squirrels & rabbits. Domed pellets are usually the basic all around start for Hunting & Target. Try the Crosman's,RWS, & Beeman's first. You will need any where from 100 to 1000 shot break in period before you can tell what pellet the gun likes. When I got my RWS 34, the first thing I did was to clean the barrel of the factory gunk. Then I ran some patches thru, 10 times or so, with some non embedding bore paste. Then cleaned that out and patched in a very very small amount of bore oil and started the shooting break in .Clean, maybe every 1000 rounds. Do not use a wire brush. Hope this helps.
