Vests are classed for the type of protection you want. Even if you get a vest designed to take say a 45 auto though it won't penetrate to you I can guarantee you will get one hell of a bruse from it.
A few years ago one of the companies that made body armor (I think it was second chance) the owner said he would be tested with a live round and was. That was his marketing gimmick.
By the way all body armor makers have a policy if you take a round they will replace the vest for free.
