You are in uncharted territory, but I suspect Jim Tarleton knows the answer to this one. He is the most knowledgeable expert on Marine WWI A5 lore that I know of.
The answer is very simple. Niedner (note correct spelling) bases used on early commercial rifles often had wings. It varies as to time frame. When it came to military rifles, Niedner went wingless to avoid obscuring the serial number of the rifle, which irritated the military.
Good luck in your search.
Last edited by Zevron; 03/03/17 06:50 AM. Reason: Spelling
