M&P 15 upper reciever question

texit · #1 05-14-2012, 09:16 AM

I have a square marked on my upper receiver under the rail.

What does this square signify? It's on my new M&P 15 OR.

crracer_712 · #2 05-14-2012, 09:31 AM

Quote:

Forging marks/makers. ( from another site)

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
Square: Brass Aluminum

This is the most common association to markings posted accross the internet.

oneyeopn · #3 05-14-2012, 09:32 AM

You beat me too it Rod, I was going to link that thread!! LOL

oneyeopn · #4 05-14-2012, 09:33 AM

My new upper receiver is Cerro Forge

texit · #5 05-14-2012, 09:45 AM

Thanks guys!

It looks like Brass Aluminum Forging Enterprises also makes uppers for:

Rock River
Delton
BCM
CMMG
Fail Zero
CD Defense
Colt