Being a newbie , I have searched for threads on this topic with negative results ! When I bought my new Gen.4 19, I had trouble with feeding and ejection. I caught a pair of Glock representatives at my local gun shop and was told,by them, that Glock would soon offer replacement recoil springs because they know that the issued ones on original Gen.4 19s were way to heavy. I still have the gun put away pending being able to obtain a suitable Gen.4 spring for it. My local gunshop's attitude is that I bought the gun and I own it , problems and all ! Seemed to be the Glock representatives attitude too. Does anyone know if there is a proper recoil spring available for this gun yet , telephoning Glock is a loosing battle.