calling all experienced APS owners

[Reno-CG]

hello, I use an aps2 sv. My gun at first was incredibly accurate when i was younger. It is not very accurate now. I bought a new hop up chamber because my original assumption was that the hop up was messed because I accidentally left it outside for a few nights in the rain (pointing up -don't ask). It is still however not very accurate. The cylinder has been tampered with because it got warped due to the spring guide coming apart inside the cylinder. I bent the cylinder back into shape and it loads fine but I still dont think it is completely cylindrical anymore. I just ordered a new FF teflon cylinder (good buy? or no?). If that is not what is wrong with my gun then what could be? Does a super hard piston eventually stop working effectively? Any comments would be very helpful. Thanx for your time -Rory