Unknown cartridge-5.56mm from Portugal

Hello, I have been a member for some time. Sorry, posting items is a little new to me. A friend gave me a round that is headstamped FNM 84 25. My friend said his brother brought these rounds back from the military in the early 60’s. The infired round sorta looks like a 223 round but has no NATO mark. I was wondering if it was some type of early prototype round. A Google search mentioned it was a commercial round from Portagle. I though that FNM was a Mexican headstamp. Thanks, joe

Your round is almost certainly Portuguese, from Fabrica National de Municoes.

Mexico also used “FNM” on headstamps, standaing for Fabrica Nacional de Municiones.

I don’t know what cartridge you have becuase your description is too tentative for a positive identification. I assume it is 5.56 x 45 mm (.223)
and it need not have a NATO mark to be such. It could have been a contract for a non-NATO country or a loading that did not meet the NATO STANAG.

Thank You Mr JohnMoss, I will take some measurements and post again. Take Care, joe

John–I assume you had a case of miss-guided fingers when you typed “4.46” above and meant “5.56”. I only mention this because Portugal has experimented with some 4mm rounds.

Ron - you are correct. I do everything in a hurry these days - some days its needed, but its becoming a habit even when its not. I have corrected the error in my reply.