Well good luck with that, may be a bit difficult because A5s dont have a delta assembly. If you are looking for good quality I would suggest Daniel Defence (DD) they have licenced their products to Madbul. I'd suggest maybe starting with a cheaper chines clone until you perfect how you will attach it.
Here is a link to a Canadian retailer:
http://www.airsoftparts.ca/store2/in...ex&cPath=65_85
Good luck.