TACOM is not the usual purchase agency for the Army. Unless, of course, you want to buy a tank or a truck.
There has also been at least one additional purchase of side-arms for the Iraqi police and military, as they will not be armed with Sigs, HKs, or the M9.
I agree, don't listen to armchair commandos, or people who's knowledge is at least 18 months out of date.
Oh, and several units have purchased different hand-guns for specific purposes with discretionary funds made available for just that purpose. The caliber has been usually 9mm and .45 ACP, to take advantage of logistics, but the unit armorers handle the upkeep. This isn't WWII, and we aren't reconstituting battalions that were chewed up by the enemy. Units remain pretty much in one AO, with little real movement.