No, this is not another which is better, 9 vs 40 thread. Well, not exactly anyway. I know both are proven cartridges, so no need to get into that debate. I like Both. We've decided (the Wife an I) to consolidate our calibers, sticking with .223 for our rifles (R700 and AR), and then either 9mm or .40s&w for our handguns (with the exception of me getting a 10mm like a G20). I have the models in my sig, and can not for the life of me decide which to keep. I plan on having a sub-compact, compact, and full-size or long slide of said caliber once we decide. I shot my 23 and 19 today for an hour or so (about 50+ rounds each), along with some .357 sig out of my 23 just because. I used 180gr winchester white box FMJ for the .40s&w, and a mix of either 124gr or 147gr Rem and Fed FMJ 9mm. The idea behind this exercise was to see which I shot better, then that would be the caliber I chose. Well, after various rounds of fire (6 rounds each time, with three targets one at about 10, 12, and 2 o'clock, 2 shots for each, varying in distance from 10-20 feet out), it seems I shoot both my 19 and 23 about the same. I'm still shooting a bit left, but my groups with each are similar. So here are the pros and cons I have so far, any input is appreciated. 9mm Pros: Cheaper More capacity (+2 over .40 with most all mags, except 26 is +1) Lighter More readily avaiable Used by more government agencies, meaning more in circluation I believe Cons: Seems less potent than .40 (this is assumed because of less felt recoil, feels like less "power") No conversion barrels .40s&w Pros: Seems more potent (again due to felt recoil) .40 Glock models have great conversion options (like .357sig) Still very readily available Used by plenty of government agencies, so there's plenty in circluation I believe Uses same dyes as 10mm when reloading, which will be something I want to get into real soon; and I plan on owning a G20 Cons: Heavier More expensive Less capacity So, to recap. I'm not looking for someone to make up my mind. I just want to hear everyone's opinions on the two, why they chose one over the other, and of course to see if there's something else I'm missing that will maybe help me make this decision already Thanks and God Bless!