I don't know about any piggies, but wearing a modern set of personal SWAT gear, seven bullets all hitting the vest, would be devastating to a persons ability to fight back for an hour or so, but not deadly.
Of course, it has been proven that a vest's effectiveness depends mostly upon the energy of the bullet that is fired into it.
Seven - nine millimeter rounds hitting you in the chest at close range would kick your ass, no matter if they penetrated or not, but a vest would most likely keep you alive.
My first .300 Magnum round (the only hunting rifle I own that has not yet taken game) would knock you completely out and still not penetrate the vest with my typical Nosler hunting round. Imagine a small sledge hammer hitting your vest at over two hundred miles per hour (similar energy involved). You could not even keep your consciousness, much less your balance or the ability to hold a sight picture.