I should have thought this one through before going! I kept the normal 20lb spring in I use for 10mm shooting. Bad choice! No problem with how the 9mm shot in with the 10mm upper. Extraction was just fine but ejection was not so good! I started from weakest to strongest and Remington 115gr was hanging the brass every shot. After that I put the little hotter PPU Partizan 115gr through and had one about every other shot but did manage a string of three good ones in a row. My last 9mm round was the screaming Underwood 115gr +P+ and that cycled pretty darn well except I had one that hung up. EAA ships some of the pistols with 11lb and 12lb recoil springs in the case and now I know why! Glad I didn't toss them in the trash and will try again next time with these. In the 6" Hunter shooting even the hottest 9mm you can't get a real fast slide to kick it out properly unless it's extreme 9mm (using this spring at least). Looking forward to trying again with the weakest spring I can find but happy for now!