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Posted: 10/28/2012 5:25:27 PM EDT
[Last Edit: Augee][Edited]
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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 
image courtesy of schaz42p EMCO: E MP 5.56 NATO 1/7 
image courtesy of schaz42 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. "Big Button" forward assist with relief cut: 
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 |
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Augee,
I have here what I believe to be another type of FN A2 upper. It has a keyhole marking next to an F marking. I bought this upper from another member here some time back. It does not have M4 ramps in it, so I assume that it's meant for a full length rifle. I took this pic with my IPad and the camera on it really sucks. The F is to the right of the keyhole. 
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Newbie here, recently bought 2 PA stripped lowers, and one rifle I want to build with the A2 upper (I think) I like the look. Anyway anybody know of ANY in stock Stripped A2 uppers anywhere? From my understanding if you have the stripped Lowers & Uppers BEFORE a ban you will be ok to find and build the rest of the rifle, correct?
Any direction appreciated. Love the site and all the wisdom 
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| I just completed purchasing all the used A2 uppers at the local gunsmith's shop. Combined with the two A2s on guns I already own I've got a total of 2 AFs (Olympic) on guns, 4 CM, 1 EM and 1 FM stripped USGI takeoffs. Any suggestions what to do with the takeoffs? |
Arfcom: I came for the tech, I stayed for GD
Proud member Team Ranstad
Proud member Team Ranstad
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Originally Posted By hun001:
my A2 upper has an "M" .. the FN barrel has a lock washer .. and the flash hider is A2 but it's offset. not at 3 and 9 . i would like to know what the M means.  Not sure who manufactured your A2 upper, but the "M" forge mark stands for Mueller Industries. |
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Originally Posted By Pro2ndAm:
Not sure who manufactured your A2 upper, but the "M" forge mark stands for Mueller Industries. Originally Posted By Pro2ndAm:
Originally Posted By hun001:
my A2 upper has an "M" .. the FN barrel has a lock washer .. and the flash hider is A2 but it's offset. not at 3 and 9 . i would like to know what the M means. Not sure who manufactured your A2 upper, but the "M" forge mark stands for Mueller Industries. thank you .very much. |
| I have a really odd one. I bought it as a complete upper from a member here several years ago. It is a Colt M4 barrel (dated 8/98 with an F-marked FSB) mated to a Colt (Mueller Brass) A2 upper. The odd thing is that the upper itself has a "4" above the gas tube star, and it DOES have M4 cutouts on the upper as well. My understanding is that none of the A2 uppers had M4 cuts, but this one does. Doesn't look like a "Bubba" job that somebody did in their garage, either. |
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Originally Posted By buckandball:
M4s did not begin life with detachable carry handles when originally developed... Sounds like you simply have an early M4 upper. I have the book "Black Rifle II," and I can't find any reference to this. Seems I had run across a reference to them once, but I can't relocate it. I thought all M4 uppers were detachable carry handle types. At any rate, thanks for the info. |
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Originally Posted By arfn:
I have a really odd one. I bought it as a complete upper from a member here several years ago. It is a Colt M4 barrel (dated 8/98 with an F-marked FSB) mated to a Colt (Mueller Brass) A2 upper. The odd thing is that the upper itself has a "4" above the gas tube star, and it DOES have M4 cutouts on the upper as well. My understanding is that none of the A2 uppers had M4 cuts, but this one does. Doesn't look like a "Bubba" job that somebody did in their garage, either. It's most likely an RO777 upper - the RO777 and RO779 were the post-M4 fixed A2 carry handle variants, and rollmarked "M4/M16A2E." There's been a great deal of debate about whether or not the first USGI M4 Carbines were fixed carry handle variants (presumably RO720) or flattop variants (RO920). However, it's generally agreed that it would have only been one production run that had fixed carry handle uppers, manufactured in late-1994. If yours is factory, then a 1998 barrel would preclude its being an M4 upper. The RO777 was the "post-M4" versions of the RO727 carbine, which used earlier 7xx-series parts, including a slightly different barrel, different feedramp angle, an old style lock nut for the receiver extension, and a two position receiver extension. "True" 7xx series barrels are often marked not with a "C MP" but a "(C) MP" barrel marking. Another option is that it is simply an earlier M4 barrel that's been installed on an earlier Colt carbine upper - the RO727/729, the RO733/735, and R6520, as well as the RO777/779 all used upper receivers with fixed A2 carry handles and extended feedramps cut into the receivers - most were marked with either a "4" or "M4" above the gas tube. The "C MB" marking is the most common on the M16A2 Carbine vintage uppers, just like the "C AF" of early M4 and M4A1s. ~Augee |
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Originally Posted By Augee:
It's most likely an RO777 upper - the RO777 and RO779 were the post-M4 fixed A2 carry handle variants, and rollmarked "M4/M16A2E." There's been a great deal of debate about whether or not the first USGI M4 Carbines were fixed carry handle variants (presumably RO720) or flattop variants (RO920). However, it's generally agreed that it would have only been one production run that had fixed carry handle uppers, manufactured in late-1994. If yours is factory, then a 1998 barrel would preclude its being an M4 upper. The RO777 was the "post-M4" versions of the RO727 carbine, which used earlier 7xx-series parts, including a slightly different barrel, different feedramp angle, an old style lock nut for the receiver extension, and a two position receiver extension. "True" 7xx series barrels are often marked not with a "C MP" but a "(C) MP" barrel marking. Another option is that it is simply an earlier M4 barrel that's been installed on an earlier Colt carbine upper - the RO727/729, the RO733/735, and R6520, as well as the RO777/779 all used upper receivers with fixed A2 carry handles and extended feedramps cut into the receivers - most were marked with either a "4" or "M4" above the gas tube. The "C MB" marking is the most common on the M16A2 Carbine vintage uppers, just like the "C AF" of early M4 and M4A1s. ~Augee Originally Posted By Augee:
Originally Posted By arfn:
I have a really odd one. I bought it as a complete upper from a member here several years ago. It is a Colt M4 barrel (dated 8/98 with an F-marked FSB) mated to a Colt (Mueller Brass) A2 upper. The odd thing is that the upper itself has a "4" above the gas tube star, and it DOES have M4 cutouts on the upper as well. My understanding is that none of the A2 uppers had M4 cuts, but this one does. Doesn't look like a "Bubba" job that somebody did in their garage, either. It's most likely an RO777 upper - the RO777 and RO779 were the post-M4 fixed A2 carry handle variants, and rollmarked "M4/M16A2E." There's been a great deal of debate about whether or not the first USGI M4 Carbines were fixed carry handle variants (presumably RO720) or flattop variants (RO920). However, it's generally agreed that it would have only been one production run that had fixed carry handle uppers, manufactured in late-1994. If yours is factory, then a 1998 barrel would preclude its being an M4 upper. The RO777 was the "post-M4" versions of the RO727 carbine, which used earlier 7xx-series parts, including a slightly different barrel, different feedramp angle, an old style lock nut for the receiver extension, and a two position receiver extension. "True" 7xx series barrels are often marked not with a "C MP" but a "(C) MP" barrel marking. Another option is that it is simply an earlier M4 barrel that's been installed on an earlier Colt carbine upper - the RO727/729, the RO733/735, and R6520, as well as the RO777/779 all used upper receivers with fixed A2 carry handles and extended feedramps cut into the receivers - most were marked with either a "4" or "M4" above the gas tube. The "C MB" marking is the most common on the M16A2 Carbine vintage uppers, just like the "C AF" of early M4 and M4A1s. ~Augee Thank you for the information. I double-checked the barrel, and the date I gave was wrong. It is 3/95. Does this tell you anything more about the upper? I had planned on pinning on an A2X flash hider, and using the upper. Does it have any value other than as a run-of-the-mill Colt upper? |
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Originally Posted By arfn:
Thank you for the information. I double-checked the barrel, and the date I gave was wrong. It is 3/95. Does this tell you anything more about the upper? I had planned on pinning on an A2X flash hider, and using the upper. Does it have any value other than as a run-of-the-mill Colt upper? Wouldn't really change my assessment, no. It doesn't really have any "more" value, though it's a rarer configuration, it's a limited market. ~Augee |
| I bought a A2 in 12/95. Ser # GC007XXX. It came in the box and had a model # of 6721. It is a flat top A2 with a 1990 lower and 1995 upper(6721). After a couple of months researching I now have the paper work from colt who they sold the (182) weapons all the way to me that backs up the gun. Why can I not find more information on this variant of the A2 carbine? The gun has a gray lower and the upper in a slightly darker gray. I have owned several pre ban guns over the years but this is by far the best shooting and accurate of them all. The question I am wondering is why is this gun not listed as a 6721 by ser # like the BC <000134 guns are? All of the markings on the gun matches the 6721. |
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M16A2 741 clone (Colt M16 factory upper assembly on Colt Pre-ban AR15A2 lower assembly). The pic is not mine but is exact in every detail, including the Colt scope. I sometimes put this upper on my BFI Full auto (NFA Form 4) lower for real fun!
http://i345.photobucket.com/albums/p367/dirtygary1/Firearms/6nFjE8c_zpsrws31ij6.jpg |
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Anyone know anything about a "A" on an A2 upper receiver? The top of the A is a little funny, in that it looks like a triangle, and it's split horizontally. P.S. I should say it's not the same as the one on my BCM upper, but VERY similar. From what I'm reading and looking up, it may be a stylized A and H combination mark for Anchor Harvey? 
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Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive. Those who torment us for our own good will torment us without end for they do so with the approval of their own conscience.
-C. S. Lewis
-C. S. Lewis
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Originally Posted By jcrowl:
How about CAPCO of Grand Junction Colorado? Picturing it here right after; sitting on NDS A2 lower. Please note how the CAPCO upper is not at all neither black nor Colt grey. It's its own color shade, closer to a dark grey-green. 
Capco Military Surplus A2 Upper by SoloDallas, on Flickr I will take closer and better pictures for everyone to have as a reference here. ETA As promised, a bit more detail; Bushmaster upper on top, Capco on bottom 
A2 Uppers (Bushmaster, Capco) by SoloDallas, on Flickr 
A2 Uppers (Bushmaster, Capco) by SoloDallas, on Flickr |
*Born in Texas, raised in Europe. Will die in the USA*
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These are all new FN uppers. Bags were marked with FN Cage Code. Top A2, A4 with rifle ramps, bottom two M4 feed ramps.
Attached File CD |
De Oppresso Liber
Iraq: 91,03,04,05,06,08,09,15&16'
Afganistan: 09,10,11',14',17' & 18'
Iraq: 91,03,04,05,06,08,09,15&16'
Afganistan: 09,10,11',14',17' & 18'
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Originally Posted By Combat_Diver:
These are all new FN uppers. Bags were marked with FN Cage Code. Top A2, A4 with rifle ramps, bottom two M4 feed ramps. https://www.AR15.Com/media/mediaFiles/32677/IMG_1905_JPG-733880_jpg-739487.JPG CD Are those being used to built new issued uppers from parts? |
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Originally Posted By USGI:
Nice. Are those being used to built new issued uppers from parts? Attached File CD |
De Oppresso Liber
Iraq: 91,03,04,05,06,08,09,15&16'
Afganistan: 09,10,11',14',17' & 18'
Iraq: 91,03,04,05,06,08,09,15&16'
Afganistan: 09,10,11',14',17' & 18'
Hey, I'm new here and decided this was where I would make my first post! Anyway, here's a picture of a slick side A2 upper on a Colt LMG, there's even a video to go along with it, at 1:05.
https://www.youtube.com/watch?v=9WIROZycUE4 |
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@Augee
I have a CM marked XM gray large hole A2 upper if you need pics for this thread. I believe it to be from a parted out SP2, it was acquired from the EE a few years ago. I also have a Square and Keyhole forge marked uppers if you need those. |
Lookin' California, feelin' Minnesota
Proud to be one of Nortega's retards
Proud to be one of Nortega's retards
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Originally Posted By Augee:
Both raised and stamped "F" markings. Probably something I won’t find a definitive answer to, but I was wondering if anyone has any insight into the marking style. I’m working on an FN clone that was probably produced in the late ‘90s and saw service in Iraq in 2005-2006. Thanks! |
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Monkey wrench in the works here. Just got two of these thru the military supply system. 3S679 marked (FN cage code) C for Colt and Square (Brass Aluminum Forging Enterprises).
Attached File Attached File Attached File CD |
De Oppresso Liber
Iraq: 91,03,04,05,06,08,09,15&16'
Afganistan: 09,10,11',14',17',18'&19'
Iraq: 91,03,04,05,06,08,09,15&16'
Afganistan: 09,10,11',14',17',18'&19'
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This is a variation on the FNMI / Kaiser Aluminum (FK) raised forge mark in the OP. The diagonal arrangement of the two letters matches what I have seen on almost every Army FN M16A2 that I’ve come across personally. This particular rifle was photographed a month ago, along with a second one with the same forge mark, both mid-production FNs from the 71903XX serial number range. I also have photos of early FNs (with the dot peen marking style lettering on the lower) that have this same forge mark. Unfortunately, I haven’t seen many examples of this style on the civilian market. Most FK uppers match the one in the OP. Attached File |
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Here's another FNMI / Kaiser Aluminum (FK) variation that I just picked up. The difference is subtle from the one above, but the K is slightly lower on this one, whereas the previous one above has the top of the K in line with the bottom of the F. Possibly just a production variation or made from another mold.
Attached File |
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| I know this is an A2 message board but I have a question about an A1 upper that someone might know the answer to or have a suggestion. I just built a retro 20inch with an A1 upper on a standard lower. I know the front pin holes are different sizes. I bought the reducer bushing from JSE. It seems to rotate and and not sit in place making the upper & lower to not sit properly and for the gun to not function properly. My next step is to drill out the lower to match the upper. Any other ideas? Thanks in advance. |
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