Okay, another work in progress so we can get the A2 Forum "up to snuff."  

As with the lowers guide, I would like input and help!  This one is a bit less "advanced" as I have gone "picture farming" just yet:

As far as I know - four companies have provided M16A2 upper receiver groups to the U.S. military for use on M16A2 and M16A3 rifles; Colt, FNMI, EMCO and Sabre Defence (unconfirmed).  

EMCO provided conversion "kits" to the military (primarily the Air Force) to convert over older M16 models to A2 specs.    

Upper Markings / Forge Codes:

Colt:

C MB



C M



C A

C AF



C K
C [Cerro Forge]

As far as I can tell *all* Colt forge marks have been raised "C," unlike the their flattop uppers.  

FNMI:

F MB
F K



F A


Photo courtesy of HenryKnoxFineBooks

F [Cerro Forge]



Both raised and stamped "F" markings.

EMCO:

E MB



E (?)



Stamped "E"

Sabre Defence:

Unknown

Barrel Markings:

Colt:

C MP 5.56 NATO 1/7



FNMI:

FNMI MP 5.56 NATO 1/7



3S679 MP 5.56 NATO 1/7



EMCO:

E MP 5.56 NATO 1/7

Most M16A2 and M16A3s should have the muzzle device (A2 comp) timed with a peel washer, though later production and recent rebarrels may have crush washers.  

Also, some A2 comps have been documented on USGI M16A2 uppers that have offset wrench flats, rather than having the flats at the correct 3 / 9 o'clock orientation.  

Forward Assist:

USGI M16A2s could have both "big button" forward assists (early) with relief cuts for the A2 style lower forging, as well as current "small button" forward assists.  

Needless to say, this guide is nowhere near complete, and I'll start plugging things (mostly photos) as time goes on.  

Anyone that has got photos already, has information that adds to or conflicts with anything posted, or has more variations they know of and want to post - feel free to post, and I can start updating the OP to reflect!

Those with access to USGI M16A2s and M16A3s are especially helpful!  

~Augee

Augee, you are awesome. Are we going to do just rifles or visit the 727 ambiguity?

FN - AH

these need to be "stickied"

When I was posting these, I was thinking of doing an M16A2 Carbines variation thread, too, but I decided it was more than an I wanted to tackle at the moment.    

The sheer number of photos I'd have to collect just to do a RO723 and RO727 variation thread... jeeze.  

~Augee

Would love to see a 653, 633, 727, 723 thread.

And a AF GAU/GUU thread

I second a GAU/GUU thread......but wouldn't that be inthe retro forum?

-Rico

To truly capture the "awesomeness" of the GAU/GUU, they need their own forum

What is the L K forge code?

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How about just the "K"?

Mike B

Kaiser Aluminum

I had one that came on a surplus FNMI upper/barrel. I sold it, but may have pics still. I always thought it was odd as I had never seen one like that before...





Wrench flats are in a USGI barrel nut wrench to show orientation:

No answer on the L K?

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Was out of town for the holidays, not much internet.  

I don't have exact documentation for the "LK" forge mark, but it's reported to be FN / Kaiser.  

~Augee

didn't Bushmaster supply a small number of rifles?

I thought LK was bushmaster.  I have an FN Kaiser and it's marked F K

Honestly not sure.  Like I said, I've "read" that it's FN, but there's been a lot of misinformation floating around on the net.

crackedcornish - there have been a lot of rumors about Bushmaster supplied ARs to the military, but there have been about Mattel, too.  No documentation other than hearsay has ever been presented to suggest that any Bushmaster rifles or carbines were ever accepted as "USGI."  

On the other hand, there's a lot of documentation of many other obscure parts and manufacturers that can all be verified.  

Reportedly Bushmaster sold about sixty-five carbines to the government in the 90's.  No verification on what they were for or where they went, and no suggestion that they were "USGI."  My guess is that they were backdoored FMS to someone to gain support abroad for the U.S.  Either way, it can't be verified, but sixty-five is such a small number of examples that they are borderline irrelevant.  If you want to count sixty-five carbines, then you may as well count every National Guard unit that's purchased TAPCO parts on ONS statements as "USGI" as well.  

Otherwise, no documentation of Bushmaster or Quality Parts has ever been discovered, whether they're contract awards, photographs, official mention (like in supply books and inventories).  

Bushmaster did receive a small contract in 2009 for M16A3 and M16A4s, but Bushmaster was unable to deliver, and as far as I know, no rifles were ever produced under that contract - despite the fact that even the short lived Sabre can be documented photographically.

A few years back, a member in AR Tech who was a supply guy in 2ID found one Bushmaster "snake" marked, select-fire carbine with a (IIRC) 1/9 HBAR.  However it managed to find its way into their inventory (repossed FMS item, confiscated from a contractor, change of serial number paperwork, who knows) it did not seem to indicate any kind of "USGI" status for Bushmaster weapons.  

While I'm open to all possibilities that have appreciable evidence behind them, I've not been able to find any real evidence that USGI Bushmaster weapons of any configuration exist, nor has anyone else who has claimed to have seen them, or whom I've challenged to provide evidence.  

~Augee

Saving from Archive rollback - still a work in [slow] progress.

~Augee

My Colt 727 clone has a C/MB(Mueller Brass) upper receiver with a "4" stamped above the gas tube hole. It is the gray color so I used a McKay A2 lower in gray from Nodak Spud. The rest of the carbine is Colt.

I dont know.
sure they did/do supply training rifles like the one in the pic below taken from the Navy website



ETA1:


another pics from the USN website shows a FH with offset wrench flats on a FK marked upper.



ETA2:
big button FA found on the USMC website


ETA3:
EMCO marked barrel (pic is not mine, just have a small collection on my HD)

once read it's "LAR / Kaiser" somewhere.
if I'm not mistaken it can be found on A1 receiver and I dont think FN ever made those.

ETA:
found a few more pics for you Augee:

there's a complete M16A2 for sale marked US Property with the large FA: HERE

an interesting A2 receiver is the one without FA made for the Colt LMG:
HERE and HERE

i got a F/keyhole marked upper if you want a pic??

LAR / Kaiser , I just checked it against the forges codes I have saved.

I've got about 5 or 6 of those floating around.... I figured they were rejects.

I've looked everywhere and I can't find out what this one is:

i saw those in the EE, i assume bushmaster?? and i assume that set screw is to keep somebody from turning the windage knob once its sighted in..

Mega?

Mueller Brass (now Mueller Industries) made forging for Bushmaster.
http://www.muellerindustries.com/






 



 

I have seen and used Bushmaster rifles in the various Engagement Skills Trainer facilities.  Just conjecture here, but maybe the small number of rifles they supplied were converted to operate on compressed air in these facilities.  The link below is to an archived professional soldiers thread regarding the use of Bushmaster rifles in the simulators.

Link to Archived Discussion

"The Rumor" is 65 rifles.. There are more then 65 ESTs.

Second, Bushmaster called them in their ads "M-16A2 carbine M4" to "US Army Special Operations Command"... At that point in history, the only M4s in Army service were COTS purchases of Colt 727s/723s for Delta, Rangers, and other SOF units. Would make sense Bushmaster "M16A2 carbine M4" would be the same type.

The US Army COTS carbines seemed to have disappeared into the system, and have never appeared as an ANAD rebuild.

I have an A2 upper with a 3 dot keyhole forge mark. I asked in another thread about it's orgin but got no response. Any help here?

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Your upper was forged by Cerro Fabricated Products:  http://www.cerrofabricated.com/Markets_Firearms.htm