and ignore armor or reduce the effect of it GREATLY
Nope, just double damage.
"Bonus to shields" doubles the damage when applied to shields. However, Higher raw damage does
proportionally more damage to all armored objects. You are going over the threshhold of negated damage more. I'll explain it with an example of extremely simplified & exaggerated math.
50 armor shield. 60 damage from a swing. 10 damage gets delivered to shield HP.
50 armor shield. 60(2) = 120 damage from a swing. 70 damage gets delivered to shield HP.