Upper reciever has key hole marking???

[pyscodog]

My receiver has a key hole mark on it. A friend has 3 100% RRA rifles and all three have the same marking. How many other brands have this mark and what does it mean? All made by the same company? I think the YMH has them also.

 

[pahntr760]

Proof Mark?

 

[Widow maker 223]

Forging mark. All were forged by the same company. There are only a few making upper and lower forgings.

 

[Widow maker 223]

Forging marks/makers.

Square= brass aluminum forging

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

 

[pyscodog]

Thank you kind sir!!

 

[Terry N.]

The 'keyhole' marking indicates that it was forged by Cerro Forge. They frequently add another letter (or two) to denote what company that run was made for, but not always.