The rules for the AMS special state it "only works on attacks coming in from the front arc, unless mounted in a turret". (2nd ed, p46).
Which "front arc" does AMS actually protect/cover (assuming no turret)?
a. the bit over 180 degree front "firing arc" (as per the firing arc diagram on p35)
or,
b. the 300 degree front arc as per determining attack direction (as per diagram on p39)
Thanks!