5.45x39mm in general, and 7N6 in particular, is relatively high velocity, narrow, and high sectional density. Recall that in an earlier test .223 Rem 45gr varmint defeated the Level III armor at 3,238 fps. The 53 gr 7N6 hit at 3,167 fps, so there is a small decrease in velocity but also an increase in mass and sectional density. Also bear in mind that the armor is rated to stop 7.x62x51mm M80 ball. Don't cheat, make your prediction before you watch the video. What do you think will happen?