Identify My Upper?

[stevegun 1]

Can anyone tell me who made this upper? The only marking is a symbol that appears to be an old fashion "key hole" outline above the forward assist.

[Whelenon]

I've got the same marking on my receiver. Yankee Hill Machine machined the casting but I suspect this is a foundry marking. If other machine shops use the same foundry castings I know not. I'm sure a more knowledgeable Horde member will clarify.

[hobbesgunner]

Cerro Forge ....hard telling who machined it...have a Bushmaster, Yankee Hill and Model 1 with that forge mark on it....Yankee Hill stamps a Y on theirs

[babaganoush]

My RGUNS NiB upper has the same mark. No idea where they get theirs from.

[stevegun 1]

Thanks Hobbes, further investigation shows your right on the money.

[Keep The Change]

Aero Precisions have the same mark.
Since other brands have the same mark, I assume this is a foundry mark from the company forging the upper.
EDIT: I see Hobbesgunner appears to have the answer.

I've seen Aero's and others advertised as "with keyhole" mark, indicating it is a more desirable forging. You might try AR15.com. I bet somebody has the answer before noon.

[LRRPF52]

It is a forge code from the aluminum forger. They start out as a plate, which is pounded into a blank, then the plate is cut off. You can still see this plate line on most of your forged lowers. Several machine shops buy those raw forgings in bulk, then run them through a CNC.

There are very few castings on the market these days, although I had one of the old ones from DPMS-an A-15 cast lower with some different external features.

Here's a more elaborate list of forge codes and who machined them/who did the forgings:

The forging mark has little meaning as to who actually finish machined the upper receiver. Cerro supplies raw forgings to AR manufacturers who finish machine the parts. I've seen them on Colt, Bushmaster, DPMS uppers, etc....


Forging marks/makers.

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

[BigBluePup]

The 80% lowers from Ares Armor also have the same key hole mark on them.

[Peck1631]

So basically there isn't a real way to find where the upper came from?

[LRRPF52]

How important is it to find out who did the machine work and anodizing after Cerro Forge cranked out the blank"

DSA engraves their uppers with "DSA" above the gas tube hole on the receiver face.

LAR engraves their take-down pin lugs with "L" on the back of the lug.

Some companies engrave the receiver face with:

"M4"
"4"

Some have tool head engraved T-marks in the 1913 slots, while others have laser-etched, and some look etched in another more crude fashion, with big white lettering.