Help me to identify this Upper....
AR Flattop Upper, 16" 5.56 A2 Flash Hider...
Markings on the barrel are as follows:
B MP 5.56 NATO 1/9 H BAR
I guess I can take some pix if needed.
My BushMaster has the same markings, fwiw.
Just trying to figure out who made the Upper. It has the same "keyhole" marking on the upper, but those were just the markings on the barrel. That would be awesome if it was a Bushmaster. I'd feel bad for the guy I traded though. He went from a Bushmaster 16" Upper, to a Model 1 Sales 11.5" Upper!
Originally Posted by JcJ
It is a Bushmaster. MP is for magnetic particle tested. Caliber, barrel and twist.
There is a wealth of info here. AR15 / M16 FAQs
Ok, checked over the site. Lots of good info. THANKS!
Now I have two more questions....
Magnetic Particle testing? I have no clue what it does, is for, how it improves the bore....
HBAR.... WTF does HBAR mean? I thought it was just a heavy barrel, but I guess I'm wrong?
Without wanting to appear a smartass (which I sometimes am) use Google on your 'puter. There is a wealth of information available.
Magnetic particle inspection processes are non-destructive methods for the detection of surface and sub-surface defects in ferrous materials. They make use of an externally applied magnetic field or electric current through the material, and the principle that the magnetic flux will leave the part at the area of the flaw.
No, you're right.
Originally Posted by SavageEagle
The upper is Bushmaster; the "keyhole" marking indicates that the receiver forging originated at Cerro Forge.
And now, for a bit of useless (or useful?) trivia:
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
Well I'd seen some info on the process but not for the barrel. i didn't know if there was something different about how they do the barrel versus, say, a piston cylider or something.
I'd looked it up, just too much info to sift through and none of it pertained to AR barrels. I just got a bunch of tech pages about **** above my pay grade! LOL
Shooter, I appreciate your help. I know, I'm ignant. I've seen the keyhole stamp on just about every upper I've held besides the Colt uppers. Figured maybe it was just a normal thing!
If you take off your handguard it will sometimes have stamped or rollmarked the manufactor...might be the upper, might be the barrel though.
I'd rather have the Model 1 11.5" than the 16" Bushmaster FWIW- especially if 1/7.