You might find the following article helpful.
http://www.surplusrifle.com/shooting/glassinga196922/index.asp
https://www.milsurps.com/images/imported/2010/08/1-1.jpg
...
Type: Posts; User: AngelDecoys; Excluded Forums: Milsurp Knowledge Libraries (READ ONLY)
You might find the following article helpful.
http://www.surplusrifle.com/shooting/glassinga196922/index.asp
https://www.milsurps.com/images/imported/2010/08/1-1.jpg
...