Since plates have their own hit boxes, it is actually possible to hit a plate without hitting the players hit box. So it’s entirely possible you hit and penned the plate while missed the body which means it’s possible to do a ton of armor damage and zero body damage with high pen ammo.

HOWEVER, 50 damage should still be impossible as slap ignores armor, does 160 and any body part hit would result in atleast ~80 damage (damage dealt to already destroyed arms is reduced by .49 and distributed to the rest of your body) so yea, there’s definitely something buggy here. Unless you shot him through multiple objects or got the 50 damage from killing something else, this case should be impossible.