How do people kill players with overshields? I've noticed that in montages and sweats/comp, people consistently snipe people even with their spawn overshield active

I can't do this however. I've choked a couple of 7th columns due to 6 shooter not killing people and requiring 2 shots, one to destroy the overshield and another to kill the guardian. Sniping people only removes a tiny bit of their normal shield (Beloved)

So, is there anything I'm missing? Is this PC exclusive?