Friend bought used edge with approximately 5k rounds. Shot and shoots great 40 major. After about 500 rounds it started not to go into full battery (lockup). Also it is difficult to initially rack slide even with trigger manually cocked. Once you pull slide about half inch or less, it’s smooth as butter. If you let slide go it goes into full battery and shoots great. Gun have been maintained and cleaned regularly. Seems to be a lockup and unlock problem, recoil spring 12 with 2-3 k rounds. Thought it might be bent slide stop pin, switch with an very old one that I had, racked perfect no problem, then a put in a new one with the same pin diameter that he had, no good same problem. Go me baffled, any thoughts? Thanks...