XM16E1 Picture from early Vietnam War.

[Sapper740]

I haven't seen many in-country pictures of the XM16E1 in action. The Colt Model 603/XM16E1 was the first attempt at providing an improved M16 for the US Army and was a transitional model between the M16 and the M16A1 which came out in 1967. Only 85,000 were made. It was the first model to incorporate the forward assist and to use the "Partial Fence" reinforced lower receiver. I've attached the only picture I've seen of the XM16E1 in the field. The two rifles on the far left are both XM16E1's.