Stamps / symbols on AR uppers?

[pneuby]

IIRC, somewhere there is a guide to show which mark/s indicate what OEM made the upper receiver. Perhaps also who brands it for their own sale. Can anyone point me toward this? My Search-Fu is weak.

[Gunslinger808]

A (splintered) = Anchor Harvey Aluminum

AF = Alcoa Forge

C AF = Colt Alco Forge

C MB = Colt / Mueller Brass

Cardinal (stylized) = Cardinal Forge

CH = Colt Harvey Aluminum

CK = Colt / Kaiser Aluminum

Circle/Crooshairs w/"AR" = ArmaLite

CM = Colt / Martin Marietta

D (stylized) = Diemaco

DK = Diemaco / Kaiser Aluminum

E = Emco

EK = EMCO/Kaiser

E MB = EMCO/Mueller Brass

F keyhole = FNMI / Cerro Forge

FA = FNMI / Anchor Harvey

FK = FNMI / Kaiser Aluminum

FM = FN/Martin Marietta

FMB = FNMI / Mueller Brass

Keyhole = Cerro Forge

L = Lewis Machine & Tool

LK = LAR / Kaiser Aluminum

LM = LAR / Martin Marietta

M (under diamond) = Mueller Industries

PA = Capco / Anchor Harvey

PM = Capco / Martin Marietta

[pneuby]

Thanks! Is there anyone with just a plain square behind the ejection port? Or are these Alpha codes hidden where I am not yet schooled to look?

[Tim McBride]

To be clear those are forge codes, not necessarily an indicator of the company that machined the forging into something usefull.

[Racewin]

Thanks! Is there anyone with just a plain square behind the ejection port? Or are these Alpha codes hidden where I am not yet schooled to look?

Square = Brass Aluminum Forging Enterprises

http://baforging.com/wp-content/uploads ... ochure.pdf

As has been stated, they make the basic forge, then someone else does the final milling. While something being more expensive is not an absolute determiner, a higher-end/more expensive receiver is likely to be closer to "spec" than one that is cheaper. This is achieved through newer, more precise machines, better cutting tools, or even just having better standards (replacing/resharpening a cutter after every say 500 passes vs 700 passes...I have no idea what the actual numbers are).

At the end of the day, in most cases, the difference is small annoyances such as sticky take-down/pivot pins, difficulty swapping a QD scope mount from one upper to another, and/or slight rough edges (cosmetic). Once the rifle is built and set up though, the difference is often negligible.

[pneuby]

I just found that and was about to post it as you did. Thanks.
So, is there any other areas to check for markings which would indicate who did the final machine work?

[Racewin]

I just found that and was about to post it as you did. Thanks.
So, is there any other areas to check for markings which would indicate who did the final machine work?

That would be up to them. Some will laser engrave something somewhere conspicuous on the outside. I see a lot of higher end ones do the engraving because they want you to know what it is, and I see others that don't...because they are likely cheaper and not worth the extra cost of a cosmetic logo certifying that it was not made by a higher end brand .