AR15 Barrel and Bolt Stampings Information

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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