Great video, it's nice to see the Brownells XM16E1 and M16A1 side by side! I bought their BRN-601 a while back and love it. I had their XM16E1 on backorder two months ago but picked up a couple Colt M16A1 parts kits and a couple 20" pencil barrels then put together a late XM16E1 upper (about 1966) and a ~1970 M16A1 upper with the phosphate BCGs from the kits. One kit had nicer parts and furniture including the trapdoor Type E buttstock which went into the M16A1 build along with the Colt C MP B barrel I found and an A1 birdcage flash hider. The rougher looking stuff went into the XM16E1 along the barrel with a non-chrome lined bore and chamber (like the real XM16E1). And I put on Brownells furniture with the Type D buttstock and a three prong flash hider. For a while both uppers had to live on A2 lower receivers until Nodak Spud got in their NDS-XM16E1 stripped lowers. Now Brownells just got in their M16A1 stripped lower (mine should arrive Monday). They also got more XM16E1 and 601 stripped lowers. Proper barrels are in short supply right now. The Brownells 601 with all new parts definitely is a beauty compared to her aging squad members but they're going on 50 years old! It would have been nice to have the shiny new Brownells XM16E1 and M16A1 but having beat up versions is cool too.
The Mag release for the XM16E1 that is shown in the original training film made in 1966 and also in photos on other reference websites like retroblackrifle.com, does in fact have the same round lines as on the later M16A1and not the straight lines. Also the bolt release is the later style as the A1. Some forum "experts" have spread the wrong info. The very very early few numbers of XM16E1 rifles may very well have had different parts that were closer to the earlier 602 test rifles but the training films and all references say those particular A1 features were pretty much standard for the XM16E1 first. Also a few very late XM16E1 rifles did in fact get "full fence" lowers that guard the mag release but those would have been very low in number. Only a few pics and one video here on RU-vid has been found of such a late XM16E1. It has also been proven, through soldiers that have carried one, that some XM16E1 partial fence lower receivers were in fact roll marked as M16A1 rifles right after the official designation name was approved. They were really just using what old stock of the E1 receivers they had left.
