Try this link: http://www.gunpartscorp.com/catalog/...aspx?catid=239
No schematic, but some parts are still available.
Afterthought: I believe the schematic is in some the older Numrich catalogs, so if you can locate one of them, you will find it. I definitely remember having to order a new mainspring for one that I had and seeing a picture of it in the book.
Reedit: I just got out my Numrich book, and, while all the parts are illustrated, there is no schematic, per se, showing the relationship with each other, just the separate parts themselves.