I use .40 cal. 180 gr. plated round nose Xtreme bullets for practice and competition. The reason I shoot 180 gr. bullets, I need to make USPSA major power factor (165), (bullet weight X velocity divided by 1000 = power factor). I've found that I'd rather manage recoil with a slightly heavier bullet, lower velocity cartridge rather than a lighter faster bullet, with higher velocity. If you are shooting a M&P .40 in USPSA you may shoot open, limited, limited 10 or production division. Of course you are at major disadvantage in open and limited division. Production division has a minor only power factor of (125). Therefore achieving a 125 PF with a .40 cartridge is going to be expensive and unnecessary. Also may compromise your guns reliability unless your power factor is considerably higher than 125(155+). Not to mention competitive shooters in production division all shoot 9mm. Recoil, cartridge cost and recoil management are all significantly lower with the 9mm. My recommendation would be to use 180 gr. bullets with the .40 cal. cartridge. The velocity needed to make major PF is 917 ft./sec with a 180 gr. bullet. There's a lot of powder available to give you a very manageable recoil from this bullet weight. I use Xtreme 180 gr. RNFP.
