I do t think it was m16, it was stripped at the time of purchase. It has a square as a forge marking though... I don't know if that has any relevance.
The square forge mark indicates Brass Aluminum Forging Enterprises. You see it on many brands including Colt. Both my BCM and Daniel Defense uppers have the square forge mark.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek
__________________ Assumption is the mother of all ****ups. Know what you know, Know what you don't know. -Paul Pedzolt "Jack of all trades, master of none, though oftentimes better than master of one" -Mynshul