I'd like to post an in depth list of all manufacturing marks that can be seen on our AR's. I've been having trouble finding sources for this information, but have contacted Colt for some valuable information about their uppers. Biggerhammer has some info, but it is not as up to date, as I would like. Any help compiling this data would not only help me, but all of my AR15.com brothers, who undoubtedly have the same problems locating this information. Thanks in advance for your help.

The "A" is [url=alcoa.com]Alcoa Aluminum[/url]

The "splintered A"( actually an "A" over a "H") is [url=forgings.com]Anchor Harvey[/url]

The "C" is [url=continentalmachinetool.com/firearms.html]Continental Machine Tool[/url]

The "K" is [url=kaiseral.com/kaiser/kaisermain.nsf]Kaiser Aluminum[/url]

The "M" is [url=martinmarietta.com]Martin Marietta Aluminum[/url]

The "keyhole" is [url=cerrofabricated.com/products_firearm.htm]Cerro Metal Products[/url]

....theres more

I think if a full list is compiled it should be tacked up for all to use at any time.

Anybody else feel the same way?

I have an early Colt and it has NO markings at all. The bbl has C MP C. I have an after market upper and it has what looks like an A with a C
over the top of the A with the lower part of the C making the cross of the A.
Any help on this mark?

You're correct that the early Colt uppers had no forge mark under therear sight area, but Colt tdid put two small, and usually very light, inspection and proof stampings just ahead of, and slightly above, the ejection port.
The forge letter and  "C" marks didn't start until after Colt got the huge M16A1 contract during Viet Nam's buildup, and H&R and GM also got contracts. The C MP C stamping on the barrel indicates second production series, with a chromed chamber, but still unplated barrel rifling.  I think they didn't start this until after you upper was made; which would make your barrel a replacement, but I might be off on that.

BTW, I have an upper/barrel with exactly the same arrangement; unmarked under the rear sight, and C MP C marked barrel, but I acquired the two pieces sepsrately, and assembled them myself; so I know mine isn't original[:D]

I have a Bushy flattop and there is a little 'keyhole' on the right side of the upper receiver below the rail between the charge handle and brass deflector above the forward assist.

Does this mean Cerro Metal Products forged this upper?

Finally a Keyhole ID Yes somebody did some real damn good homework

Thanks guys, this is great info. I'll put together a detailed list, and maybe one of the moderators can post it.

Yes, I realize these facts for sure, I will however try to track down what companies forge them, who does the final machining, and finishing. Being in manufacturing myself, I understand that parts can go to many suppliers for different processes before the part gets assembled. I just found it interesting that the M4 upper I just bought as a "Colt" was actually a Diemaco, forged by Anchor Harvey. Being an inquisitive individual, I contacted Colt and confirmed with them that Colt indeed uses these M4 uppers. He also stated that the Diemaco M4 uppers are generally only used on LE models, and Military weapons. Colt also uses the "C" forging from Alcoa, which can also be found on civilian models

Due to the current war in Irag Civilian model production is limited. This is not to say, that you won't find Diemaco uppers on civilian AR's
or vise-versa. It was a very interesting, and informative phone conversation, The Colt Manager knew quite a bit, and was more than happy to share the info with me.( I got the feeling he doesn't get too many calls), but he was very nice.

[url=http://ar15.com/forums/topic.html?b=3&f=12&t=175914]"A" marked upper [/url]
[url=http://ar15.com/forums/topic.html?b=3&f=118&t=176964]What markings are on your Colt upper?[/url] w/pic of Diemaco forge mark.
[url=http://ar15.com/forums/topic.html?b=3&f=118&t=165524]NEW COLT M-4 UPPER MARKINGS[/url]
[url=http://ar15.com/forums/topic.html?b=3&f=118&t=175219]What's up with all the different forgings? [/url]

hmmmm, strange, my RRA flat top upper has the exact same marking...
HUNTER.

j3_,

Do you have an example of the Cardinal Forge mark?

Does it look like one of these?
[img]http://autoweapons.com/photos/accys/m4a3upassya.jpg[/img]

A _triangle_ over an "M"?
[img]http://www.muellerindustries.com/images/left.gif[/img]

Sure about that? I don't see anything about CMT forging parts on their "capabilities" page.
[url]http://continentalmachinetool.com/capabilities.html[/url]
In the past, "C" has always stood for Colt with a forge mark after.

Tweak, the bottom one in your picture is a Diemaco manufacture, Anchor Harvey raw forging I believe.

Really?  I have a C MP C marked barrel and I was told it was all chrome. Is having only the chamber chromed a problem?  Is the chrome chamber [i]and[/i]  barrel that much better?  If it doesn't matter, then why did Colt switch to all chrome?

I can understand only chroming the chamber as that's where chambering/extraction occurs and the "slipperiness" of the chrome is probably most appreciated there, but is there any advantage to chroming the barrel, outside of longer cleaning intervals?  

I've got a Chromoly steel barrel in my current AR and I clean it every range trip.  I'm a fanatic about cleaning, so I'm not too worried about it, but I am still curious, why did they chrome the whole barrel versus just the chamber?

C MP C barrels have a chrome chamber. C MP B, or C MP CHROME BORE have a chrome bore and chamber.

ETA, [s]the above poster[/s] Bartholomew_Roberts is correct. Diemaco responded that the "angular D" seen on the bottom upper is their mark.  

tagged

Alright all you "tags" there's a permanent link to this thread and related ones in the Tshooting forum FAQ.

Received an upper today clearly forged "E K" and the barrel is stamped "E MP 5.56 NATO 1/7".  Believe this to be the "new" Eagle Arms.  True or false??

False, but I can't find the thread the talks about the E marked parts. IIRC they were the same barrels rejected by the military for having rough chambers. There were quite a few threads but I can't suss the right combination of words for Search to bring them up.

ETA,

Here's a link, it's an EMCO barrel.
[url]http://ar15.com/forums/topic.html?b=3&f=12&t=171854[/url]

Guess I'll be checking chambers, test firing, possibly polishing chambers, worst case scrapping barrels.  Read the thread on EMCO, any obvious problems with the recievers?  Thanks for the info, Tweak.

Dunno about the receivers, before WPNSMAN mentioned EMCO I'd never heard of them.

Found an old post verifying Tweak's comments (had no doubt myself, just love info).

ƒÞ MSG, 18Sep01: subject: TACOM No. MAM-01-027, Converted M16A1 rifle to M16A2 rifle with ¡§E¡¨ marked barrel.  Summary: Over 90,000 converted M16A1 to M16A2 rifles using Emco conversion kits have been fielded to TRADOC, FORSCOM, Army Reserve and National Guard units.  All these weapons were fired by Anniston Army Depot when they test-fired 43 rounds through each barrel for function and accuracy checks.  Out of a group of converted M16A2 rifles fielded to Army Reserve units in 1996, Fort Dix has identified that 7 rifles from a deploying MP unit had roughness in the chambers which was affecting extraction and causing stoppages.  The Army Reserve Command issued a message to all of their units stating that "E" marked barrels should not be fired and implied a safety concern.  TACOM-RI does not consider a weapon failure to extract an expended cartridge case to be a safety issue.  A QDR for the Fort Dix failures to extract has been submitted and the situation is under investigation.  POC: Neal Christianson, DSN 793-0034 (309-782-0034), [email protected]/.

Well, what are the odds that my two barrels are part of these seven.  Math comes out to 0.00007%.  Odds are in my favor that my barrels won't be scrap after all.  Since all seven were in one unit, maybe the chances are that this was a single production run problem and not all the barrels.  Just hoping so for my sake.  In the mean time, I will tread lightly with these two uppers until they prove reliable.

Just had a thought bounce around my relatively empty skull.  If Emco was making M16A1 to M16A2 swap kits, which you would expect to have bayo lugs and flash hiders, how did I end up with two "naked" (no threaded muzzle), postban barrels.  Still wondering on that.  Emco may have catered to the civvy market as well.

How long is the barrel from the muzzle to the front of the front sight base?

Could you provide a link to the post you found? That's the one I was looking for originally as it had the "proof" included in it.

I'm pretty sure there are more than 7 bad EMCO barrels as we've had about that many reported here alone.

http://safety.army.mil/pages/media/pubs/cm/cmnov2001.doc

Then do a "find" for Emco and that gets you to the article.

You hit it with the barrel length.  These have been custom shortened, both barrels are about 3/4" shorter than a standard 20" barrel.  Appears that they cut off the threaded muzzle and machined the shoulder in them to make them appear to be "postban" barrels.  Pretty decent job of machining and the refinishing appears to be the lighter gray color.  Appears to be a pretty decent crown job on the barrels as well.  Oh well, they are mine now, so I'll either make the best of them or into the scrap pile they go.

Tagged

Thanks for the link mongo, there's still a thread floating around here from WPNSMAN that quote that same passage. I thought you has found it. Data's better straight from the source anyway. Thanks again.

Nice to see that old post still has some life left to it. If it saves someone from possibly getting burned, I hope it stays around a long time.

As to the MAM(Maintenance Advisory Message)that mongo001 quoted, it gives some background information which is helpfull, but deals with the the problems encountered in a few rifles which started this whole fiasco. I have been intimately involved with this issue from the start. I assure you, there are more than the original 7 rifles which have this fault. Right now the actual failure rate to varying degrees is around 10-12%. The Reserves originally called it a Safety issue, while technically it was a Functional issue, and correctly identified as such by Rock Island. By the way, most of my original informatin came from my contacts at Rock Island after many conversations as to the history of EMCO.

But, since the testing of suspect rifles was so mishandled and misunderstood by commands in the field, with the resulting loss of confidence in these weapons, it has been deemed to identify all rifles with these barrels for future replacement. As of now rifles with these barrels are not being allowed to accompany deploying troops.

So, as I predicted, some of these things are bypassing demil and making their way into civilian hands. Either as preban and now postban nuetered barrels that are being mistaken, or outright being sold as a major manufactures product. Do I think all the suspect barrels are trash, No. Just be sure to carefully inspect the chamber of anyone that is offered to you. But know that these are used Govt' barrels that "shouldn't" be available. Also, there seems to be a big misconception floating around that the military is "surplusing" off older M16 parts, AKA all those A1 parts now on the market. Some were undoubtedly rifles surplused to other countries and are now being imported back as parts kits. Officially unserviceable or obsolete parts washed out during the rebuild process are to be destroyed, but are obviously finding there way on the market.

As to the remainder of EMCO produced parts, all I have personally inspected seem just as good as any other milspec part as originally manufactured. But since these are used to varying degrees by now, you stand the chance of comming across a worn out and possibly refinished item.

Wpns Man

It's linked in the FAQ so barring anything catastrophic....

As I have stated before, these two barrels will be under great scrutiny until they either prove reliable and functional or trash.  Hate to take the financial hit if trashed, but I can't allow unfit parts to be put into uppers I build, shoot and potentially sell to others.  Thanks for all the great info.

[url=http://ar15.com/forums/topic.html?b=3&f=66&t=179656]Another "E" barrel[/url]



[dam brackets]

Hi Tweak. On that note...what's the origin of the "Colt" M16A1 kits that cdnn among others is currently selling...hear anything bad about 'em?
BT

Not a clue OODA, most likely more disassembled M16s from overseas.

But most of the flat top uppers does not have any markings. I've seen uppers that came from Bushmaster, DPMS, etc that does not have any "mark". Even the flat top on BM's catalog and Wilson's does not have any mark. as well as Olympic's and Les Baer's rifles and carbines? Do you mean it's "grinded" off during the machining process?

sunga,

Who are you talking to and what are you referring to? Colt flattops are marked.

Speaking of Colt flattops. What is the "B" on the carry handle of this M16A4?
[url]http://ar15.com/forums/topic.html?b=3&f=118&t=183320[/url]

Since we're on the subjct, I've been trying to find out who made barrels stamped "P MP".

Anyone know?

I [i]think[/i] but cannot yet verify that the "P" mark is Elisco Tool in the [b]P[/b]hillipines. This based solely on the serial numbers of the ET contract guns, RP xxxx.

Am in the process of checking that.

All of the "E" marked (EMCO manufacture) barrels that have turned up have been attached to "EK" marked A2 uppers. For the time being the assumption is that "EK" is Emco Kaiser. AFAIK, EMCO is out of business.


I haven't been able to contact anyone with an Elisco (Philippines) manufacture rifle to check their marks.