Regarding old AR articles - Here's another one that I am on the hunt for:
Prone to Win - Ernest J. Vande Zande (April 1981).
I have a tattered paper copy. It was given to me many years ago by as a starting point for trouble shooting and refining small bore prone position shooting.
A very useful marksmanship article, clear and concise. Applicable to other disciplines with prone shooting positions. Not something you will find in today's AR or other shooting rags.

Thanks in advance
Tom