Talk:R4 Agromech/@comment-31354887-20170713094012/@comment-454133-20170713153602

It says you cannot modify your attack dice. Since spending a focus is explicitly for modifying, I doubt that you could spend it even to modify 0 dice, since modifying any number is forbidden.

If you want a lock on the defender after a snap shot, a much easier method that's fully supported by the rules is Fire Control System, which will trigger after any attack and let you lock the defender.