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AR15 Barrel and Bolt Information


Barrel Stamping Information

Barrel Manufacturer Stampings
Manufacturers Stamp
Manufacturer
B
Bushmaster
C
Colt
D
Diemaco
FNMI
FN
SAK
SACO

 

Barrel Manufacturing Stampings
Manufacturing Stamp
Meaning
MP
Magnetic Particle Tested
C
Chromed Chamber
CB
Chromed Bore
HBAR
HBAR Barrel Profile


Barrel Stamping Methodology
Manufacturer Quality Control Caliber Barrel Twist MISC

Examples
C MP CHROME BORE Colt Magnafluxed with a chrome lined bore
C MP 5.56 NATO 1/9 HBAR Colt Magnafluxed, in 5.56 NATO, 1 in 9 twist, with a HBAR profile
 

 

Bolt and Carrier Stampings and General Information

 

(Above) Early model SP1 smooth sided bolt carrier without notches. Notches were added on later to accomodate the forward assist . For a comparison of early and later model bolt carriers, please see the SP1 Early vs Late Model bolt pictorial. Image Courtesy Don Francis

 

Bolt and Bolt Carrier Manufacturer Stampings
Manufacturers Stamp
Item
Manufacturer
C Bolt Carrier Colt
M Bolt Carier Global Sales Marines version, as produced by Smith Ent.
MPC Bolt Colt
MPN Bolt

Bushmaster (marked in paint)

N Bolt Carrier Global Sales Navy version, as produced by Smith Ent.
NM Bolt Carrier Global Sales National Match version, as produced by Smith Ent.
Shield and SE Bolt Carrier Smith Ent.

 

(Above) Colt carriers have a "C" stamped to the left of where the firing pin retainer is inserted (Left) Colt bolts are marked "MPC" on the side between the ejector and extractor pin holes - Image enhanced with red text for illustrative purposes. Bolt Stamping Information Courtesy John M.

 

Last Modified on December 31, 1999
aalbert@biggerhammer.net