AR upper question

fast18 · March 15, 2013, 11:23 AM

Hello all. I have a question on a AR upper? I know this has been asked before many times but from my research it's not answered my question. So, does the Fk marking on the upper stand for FN or bushmaster? Is the case that FN made it and sold it to bushmaster or is it really a FN upper? I've looked up the codes and some say FK=bushmaster and others say FK=FNMI? So how do you tell the difference? Also, this is a Frankenstein gun were talking about barrel upper and lower aren't from the same place so it's not a bushmaster AR. Any help would be greatly appreciated.

Quentin2 · March 15, 2013, 11:51 AM

The code or symbol stamped on the stripped upper receiver usually indicates which forge it came from. I'm not familiar with that code but usually you see a keyhole for Cerro Forge, bird head for Cardinal Forge, splintered A for Anchor Harvey Forge or square for Brass Aluminum Forge.

Anyway it shouldn't indicate BUshmaster or FN, though ArmaLite does have their own symbol on their upper.

BillyJack3 · March 15, 2013, 12:14 PM

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

fast18 · March 20, 2013, 10:33 AM

so from the markings shown its a FN upper?

March 15, 2013, 11:23 AM	#1
fast18 Member Join Date: March 5, 2012 Posts: 19	AR upper question Hello all. I have a question on a AR upper? I know this has been asked before many times but from my research it's not answered my question. So, does the Fk marking on the upper stand for FN or bushmaster? Is the case that FN made it and sold it to bushmaster or is it really a FN upper? I've looked up the codes and some say FK=bushmaster and others say FK=FNMI? So how do you tell the difference? Also, this is a Frankenstein gun were talking about barrel upper and lower aren't from the same place so it's not a bushmaster AR. Any help would be greatly appreciated.

March 15, 2013, 11:51 AM	#2
Quentin2 Senior Member Join Date: June 18, 2009 Location: NorthWest USA Posts: 1,996	The code or symbol stamped on the stripped upper receiver usually indicates which forge it came from. I'm not familiar with that code but usually you see a keyhole for Cerro Forge, bird head for Cardinal Forge, splintered A for Anchor Harvey Forge or square for Brass Aluminum Forge. Anyway it shouldn't indicate BUshmaster or FN, though ArmaLite does have their own symbol on their upper.

March 15, 2013, 12:14 PM	#3
BillyJack3 Senior Member Join Date: May 2, 2012 Posts: 423	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

March 20, 2013, 10:33 AM	#4
fast18 Member Join Date: March 5, 2012 Posts: 19	so from the markings shown its a FN upper?