.223 FMJ at under a 100 yards will penetrate most kevlar only jackets (IIA or III). Balistic plates will stop it, but the kevlar basically will not stop projectiles at 2000FPS. Works good on 1000 fps and under pistol rounds.
Here is a well done test: http://www.theboxotruth.com/docs/bot24.htm
Quote: “I’ve said it before.....rifles are rifles and pistols are pistols.”
I own and love to shoot a Remington XP-100 221 Fireball. Purchased it many years ago. What is it? Rifle or Pistol. I guess legally it is a pistol, even though it is a 600 Remington action with a short barrel and pistol stock.