I also did some armature ballistics testing at the range. I tested layers of Kevlar from cannibalized flak jackets, the groin flap from a military issue interceptor vest, and a deltoid pad from the rhino spectra/Kevlar composite copy of the interceptor. I tested a desert eagle loaded with .357 magnum FMJ and a CZ52 with Czech load steel core SMG ammo.
The .357 failed to penetrate every vest, although the brand I was using failed to cycle in my desert eagle. I’ve more or less conclusively proved that soft points and hallow points are stopped by even level 1 Kevlar vests, unless you empty the mag at close range.
The CZ penetrated a pad of 18 layers of Kevlar, then it penetrated 36 layers of Kevlar, then when I added 54 layers of Kevlar it only went through 20 or so. I need to do this again when I got back to the range.
The current military issue Kevlar pad stopped the bullet but the after market rhino armor failed to do so.