A 9mm or .45 won't go through a threat level III vest. These vests and the IIIA vest will stop almost all handgun rounds up to .357 and possibly .44. The big boys like the .454 and .50 cal will go through. Most police also wear a plate in the vest right in the chest area that will stop a .30-.30, 7.62x39mm and some others. I would choose a level IIIA with a K-30 insert personally for everyday use. I personally don't have a need for armor right now however.        rofl :rofl   Handguns dont go through armor, bullets do and it all depends on the caliber of the bullet and what you consider 'armor'.  A 9mm hallowpoint(forgive my spelling if im wrong) has generally a 50-50 chance of punching through basic police Kevlar. Armor Plated Kevlar will probably resist a 9mm round which is why I think police should use .45ACP rounds instead because theyll easily punch through most armor and the ammo is generally cheap if you use target rounds which are pretty lethal as well. 