if you are limited to ball ammo which the military is YES the 9mm is not a very good choice. I do think the m9 wasn't that great a choice but it was in a time when semi auto handguns where really transititioning to modern design. when the m9 came out what else was really out there. glock was barely out there and everything else wasn't that reliable or was a revolver, or was a single stack rounds limited 1911.
