FMJ,, I have taken 2 rounds into a vest, and it hurts like hell!!!!!
One was at less then 4ft and it came out of a 8" bbled S&W, 357mag round was a 110grain super vel,,thank GOD.
I had a burse over the left pec about the size of a baseball, deep purple,and red, stayed with me for around a month and a half,hurt like hell and make liifting the arm a little sore,, vest was an early kevlar model type 2 from a cop shop.
2nd time it was a 9mm FMJ round 124 grain military black or blue tiped, caught it dead center on the chest,just a little to the right of center line, from about 30 yards, impact casued the zpfoid bone to crunch up a little and cracked the adjoining rib,, and again a nasty bruse,, never found the shooter or weapon on that one,, so don't know if it was handgun or rifle/carbine.
The guys in Cali, were jucied,, with what I don't know, reports where never clear,, they were arressted months before for drugs and guns, but a nut case JUdge gave back the guns..
You have to understand the vest isn't bullet PROOF, its bullet RESITANCED.