Considering that you can't see effects until adult, I'd say no to nerfing the original ray in that way. Most of the (active) owners of Rrays give out free zaps so that other users can see their effects without waiting a month.
What if the Rray was re-released, and there is then a chance of them breaking like books, but say after 1K uses? Or, you start to get "warnings" on the use screen saying it is wearing out before it breaks. It could be a black market expensive item (please no to being CS) and that would limit how many are in circulation.
I'm not a fan of having ammunition for a zap ray unless the ammunition can be different items already on site. Rescreatu has wayyy too many items, why introduce another one when something already existing could be used?