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The_Dude
05-18-10, 12:08
I've been noticing that most uppers have the same little keyhole shape on the ejection side of the upper? Whats this all about? Are all of these uppers made by the same manufacturer?


Riley~~~
Slinger646
05-18-10, 12:25
It unlocks the ninja in us all....

Seriously:


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
warpigM-4
05-18-10, 17:44
C with a Keyhole is also Colt .Thats what I have on My Colt Upper
Falar
05-18-10, 19:38
It unlocks the ninja in us all....

Seriously:

Nice list.
PA1911
05-18-10, 19:47
My DD upper has a keyhole looking thing on the ejection port side below the rear iron sight. I didnt see a letter, is this what you folks are talking about? Does that mean my upper is a Cerro forging??? Does DD just do the machining/finishing??
warpigM-4
05-20-10, 16:33
Yelp thats what the Keyhole is ,A lot of Companies use Cerro Forging .
PdxMotoxer
05-21-10, 03:33
My S&W M&P has no letter just the keyhole.

I kinda wondered what it meant but didn't care enough to ask. lol
Circle_10
05-21-10, 07:30
My BCM midlength has the keyhole mark, but the BCM lightweight carbine upper i just recently got has a marking in the shape of a square, which i didn't see on the list.
Robb Jensen
05-21-10, 07:33
The square is Brass Aluminum Forgings http://www.baforging.com/.
LMTRocks
05-21-10, 23:49
My 2008 LMT has a Cardinal Forge upper. The 762x39 AR pistol I'm building also sports a cardinal forge upper.
Sierrahotel83
05-22-10, 07:50
I have an A2 upper that has a keyhole with 3 dots in the keyhole, is this the Cerro Forge as well?
osiris32
05-23-10, 09:13
I've got a Del-ton Upper ... its got a Square on the ejection side. Any ideas?
Robb Jensen
05-23-10, 10:12
I've got a Del-ton Upper ... its got a Square on the ejection side. Any ideas?

3 posts up I replied with this: https://www.m4carbine.net/showpost.php?p=660701&postcount=9
osiris32
05-23-10, 22:03
3 posts up I replied with this: https://www.m4carbine.net/showpost.php?p=660701&postcount=9 sorry didnt see that thanks
fls9497
05-23-10, 23:17
I have a Rock River Arms upper and I have the keyhole symbol. Good to know that it's used by other reputable companies.
isa268
05-24-10, 01:16
My BCM midlength has the keyhole mark, but the BCM lightweight carbine upper i just recently got has a marking in the shape of a square, which i didn't see on the list.


The square is Brass Aluminum Forgings http://www.baforging.com/.

looks like BCM switched to Brass Aluminum forgings cause the BFH upper i got the other day also had the square mark on it.
bkb0000
05-24-10, 01:21
they don't "switch," they just use what's available/cheap/whatever.
Robb Jensen
05-24-10, 05:48
looks like BCM switched to Brass Aluminum forgings cause the BFH upper i got the other day also had the square mark on it.

I currently have 3 BCM uppers. One is a Brass Aluminum Forgings and the other two are Cerro.