Go here for schematic ..syas their out of stock but at least you see what you're looking for.
http://www.gunpartscorp.com/catalog/Products.aspx?catid=4293
And it's here also. http://www.brownells.com/.aspx/pid=0/sid=78/schematicsdetail/522_Viper
It's posted but is licensed and cannot be printed.
Hope it helps.