Skinny,
I am not sure if you know about one of "The", if not
"THE", source for all things "EBR"?!?!?
Ar15.com
There is such a knowledge base there, that if you can not find it there, someone there, can (more than likely) show you where to find it.
If you need to, tell them I sent you over....
Enjoy!
Tall Shadow