The AR-10, Armalite’s first pitch to the United State’s military (thanks to Eugene Stoner) was originally rejected due to not being an M14. The rifle was instead marketed to the Spanish, the Portugese, and even the South Africans during the colonial wars and throughout the time period. They had seen extensive use in Africa by Air Calvary units, and are distinguishable by a very, very subtle difference. The charging handle instead of being towards the rear of the receiver, was on the top. And this was used instead of a bolt release. This charging handle is inside of the carry handle. This was changed with more modern AR-10’s which are pictured below.