I have carried 9mm (briefly), 357 Sig, 40 S&W, 10mm and 45 within the last year. I allowed my shot timer to briefly sway me to the 9mm; however, I soon came back to my senses :embarassed: and realized that a .01-.03 slower 2nd shot is miniscule and I could / should carry a more powerful and / or larger bullet. My preference then varied from high KE with the 10mm or 357 Sig, to the compromise 40 S&W, or 45 for maximum diameter. No more indecision. I'm sticking with 45 diameter whether it be 6+1 of 45 acp/45 GAP (Glock 36, 39) or 8+1 45 acp/45 GAP (Glock 30SF, 38) Studies that show smaller bullets (9mm) being as effective as larger bullets (45) are based on bullets hitting various places in the torso of different people. Logically, if two bullets of equal design, struck the exact same spot the bigger bullet would offer a potentially quicker incapacitation against an attacker. I'm not buying the notion that the smaller bullet will work "just as well" as the bigger one, as pictured. Stories like this are not going to sway me back toward greater capacity over diameter: http://www.policeone.com/patrol-iss...ne-cop-carries-145-rounds-of-ammo-on-the-job/ If unfortunately approached by an armed attacker (or two) in a parking lot demanding money and threatening life, a couple of well placed 45 bullets are more likely to incapacitate the attacker faster than a couple of equally well placed smaller bullets; I also think the one or two attacker scenario is more realistic than being attacked by a small crime mob where capacity would be obviously preferred. I am resolute to stick with 45 diameter bullets.