I have recently bought a Glock 20sf. And I am having extraction issues with this gun. I have made test loads and have bought some factory ammo to shoot in this gun. I have had this happen to me about 2-4 times while shooting. The gun will fire and the slide will reciprocate back and lock open due to the round that was in the chamber not coming out of the chamber all the way. The round will be about 75% out of the chamber before it will slip off the extractor. I was wondering if my loads are too hot for the standard glock recoil spring. I have bought 2 Wolff recoil springs in the 20, 22 lbs range and a guide rod from wolff also. I have not had a chance to shoot the gun since I have installed the new guide rod and 20lbs spring. I was also wondering if the extractor spring needed to be increased since it was slipping off the round. The load I am using is warm but not hot. I am loading starline brass and hornaday 200gr XTP over Blue dot powder at 9.3Grs. It is giving me about 1090-1100 fps in stock barrel the crony was set up at about 3 yards. The cases show no signs of case bulge other than slight bulge all over from the typical lose glock barrel but on par with other glock 10mm cases I have seen fired. I have a standard glock barrel and everything is stock beside the recoil spring.