Thinking about missile weapons "bypassing shields" : I'm not sure it would have any effects if the bypassing apply to the shield defense bonus. AFAIK missile weapons ignore defense altogether, they are aimed at squares and happen (or not) to hit stg in the square.
And I'm not sure the bypassing apply to the shield protection.
Lastly I don't find shield-bypassing missiles much rationalizable, unless they are rationalized as guided precision ammo
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