my p3at will start to fail to extract after about 25-50 rounds fired. after it starts to fail, it will only fail about once every magazine, sometimes more and sometimes less. my extractor and spring look good and the screw is tight. i even polished the chamber and ramp (to help the case slip out). this started fresh from the box, and i have about 500 rounds through it now. how can i fix this inconvenience, or should i forget about it and just keep the gun clean?