These receivers are really interesting if you care about the markings. Some people think they’re Colt branded made by FN for the military, others think the numbers followed by the C and A is just FNs cage code. I can’t remember what the markings mean exactly but I do remember this is a FN receiver. Either way, they’re unique and they look cool, most mil contract uppers will just have a manufacturer mark followed by the forge mark, or just a forge mark. Charging handle included
