I've been reloading 9mm for about a year now, and have only used Precision Delta FMJ and Montana Gold CMJ, both 124gr. Loading those two brands of bullets with everything else being equal, I get about the same velocity, right around 1060fps. I just got a case of Montana Gold 124gr JHP, and chrono'd them today. Using the same brass, powder charge, primers, and keeping case volume about the same, I got higher velocity from the JHPs...just over 1080fps from my 17, and just over 1110fps from my 34. I knew this was a possibility, which is why I loaded 50 and held off doing more until chronographing and function testing them. I'm curious if others have had similar experiences when moving between FMJ and JHP and if anyone has any theories as to the reason for the velocity difference.