I've chrono'd that Federal 115 gr FMJ, 9mm ammunition through a Glock 19 and got 1085 fps for an average of 5 shots. By contrast, Remington Golden Saber 124 JHPs went 1151 fps for 3 shots; while Winchester White Box 115 JHPs went 1041 fps. If any are under powered, they aren't by very much and function well in all my 9's. (Sig P290, Colt Combat Commander, Colt Gov't Model with 5" barrel, Beretta 92, and Glock 19)
I'd recheck your extractor hook, recoil spring and mainspring for wear or damage, also the chamber condition...i.e. nicks or rough machining marks.
Best regards, Rod
Cherish our flag, honor it, defend what it stands for or get the hell out. Our Freedoms are not free, they've been paid for many times over by heros in uniform. Far better men than I, died that we could be FREE.
USAF FAC, 5th Spl Forces, An Loc, lll Corps, RVN, 69-70, Vietnam Vet '69-'73