I did a small experiment today.
I first tested my Gen 2 Glock with its OEM extractor. It has an after market solid steel guide rod, a flat wire 17# spring and HRED extractor spring assy. This gun has approx 3000 rds thru it and has been completely reliable. It has always "dripped out" empties to the side and not in my face.
I loaded a mag with fifteen founds alternating WWB 115 with Gold Dot 124gr +P. Upon firing the WWB just drippled out of the gun generally to the right. The GD 124 +p ejected about three feet high and three feet right at about 4 o'clock.
I changed the extractor to a Glock 40SW and repeated the test. The WWB ejected about two feet to the right and at about 4 o'clock. A bit better than before. The 124 +P ejected about three feet high and about four feet to the right at about 3 o'clock.
1) The Glock 40SW extractor may actually be better for the 9MM Glock.
2) The Glock is definitely ammo sensitive. It is designed to work best with +P rated ammo.
3) Given the ammo sensitivity, 9MM Glocks are probably over sprung and would most likely work better with most ammo with a 15# or 16# recoil spring.
I don't know what after market recoil springs are available for the Gen 4 9MM Glocks, but if I owned one I would try a lighter recoil spring to cure erratic ejection. It is clear to me that many Glock ejection problems are related to slide velocity that is to low at the point of ejection.
As a side note: my Gen 2 40SW pistols never had weird ejection IME and they used the same recoil springs as the 9MM. What was the difference? Much higher slide velocity; a 135PF vs 175PF cartridge.
Last edited by DBR; 07-20-2012 at 22:55..