Colt 6921 Upper


Last month, there was a sale on Colt 6921 uppers. Since I absolutely don’tr need any more AR uppers, I bought one anyways.

The Colt 6921 upper is a 14.5 inch government profile M4 upper. Your bog standard M4 upper. Not to be mistaken for the 6921HB or SOCOM model, which has a heavier profile barrel (.75 inch with M203 cuts).

It comes in a nice box, and it includes a Colt AR15 manual.

The sticker on the side shows that this is part number SP401165.

The upper comes in a bag that is designed to prevent rust. It also comes with a wick in the barrel.

This particular upper does not come with a charging handle or bolt carrier group. Also there is no side sling swivel included.

It is called “Government Profile” as the government would be the only ones that would make a barrel profile heavier closer to the muzzle.

I wasn’t going to post about this plane jane upper, but then I remember there are those weirdos out there who care about stamps, marks, and the like. I figured I should post it up for reference. I received this upper from Brownells in Dec 2020.

M4 (Fat) double heat shield hand guards
<B>1 Front Sight Base forge marking
No F mark.
R stamped barrel. No white paint dot.
13629 Cage Code marked barrel.
Thin even coat of dry film lube.

Sometimes I read about someone getting a new upper and complaining that the finish is defective and grey on the inside. No, that is dry film lube.

White T marks

The front of the upper receiver is M4 marked, but I was unable to get a clear picture of it.


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