He may play the Magazine, and may put an ammo on it, but that's all. He
can't activate the ammo, since Magazine says "may use the effect of the
ammo card as if it were played from your hand."
I'd say no.
Magazine: "--- Put an ammo card from your hand on this card. When using
this gun, you may use the effect of the ammo card as if it were played
from your hand."
Zip Gun card text tells that "ammo cards cannot be used with this gun"
You cannot play(use) ammo cards from your hand to be used with a Zip
Gun. You cannot play (use) ammo cards on a Magazine with a Zip Gun.
Benefiting is very vague term, but I don't think that any gun gains any
benefit from an empty magazine - it's the ammo the magazine contains
that "benefit's" the gun (or the combination, but let's not get any
deeper into this).
I think that you can put Magazine and ammo card on a minion with a Zip
Gun. You just can't use them, however.
Best,
Heikki P.
Thank you gentlemen