Does anyone know if a 12 guage deer sabot will penetrate body armor?
I don’t know for sure but I doubt that a slug would penetrate body armor.
Soft body armor is designed specifically for that type of projectile; large, low velocity and large frontal area are what Kevlar webbing is designed to stop.
But the energy that a 12 gauge slug carries would have to be absorbed some way. You may not be killed by the slug penetrating your body but you may be killed by a broken rib penetrating your lung or heart.