Rifleman Q&A: Two Serial Numbers On An M1 Carbine?

by
posted on April 30, 2021
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
m1-carbine-national-firearm-museum-f.jpg
Q: I recently purchased a "G.I." M1 carbine. The only unusual aspect of the gun is that it has a serial number in the normal location (behind the rear sight), but the same serial number is also stamped in front of the rear sight. The two serial numbers appear to have been stamped at different times. Can you explain why the serial number was stamped on the gun twice?

A: Most M1 carbines were originally fitted with non-adjustable "L-type" rear sights. When they were arsenal rebuilt after World War II, regulations called for any superseded parts to be removed and updated components installed. One of these new components was the improved rear sight that was fully adjustable for windage and elevation.

When the new sight was retrofitted to some overhauled carbines, it could obscure all or part of the original serial number. In such instances, the serial number was re-stamped in front of the rear sight by ordnance personnel as part of the overhaul procedure in order to have the serial number visible. A carbine encountered today with two serial numbers has unquestionably been through an ­arsenal overhaul.
This Underwood Elliot Fisher M1 carbine in the NRA National Firearm Museum collection has the later ramped rear sight that partially obscures the serial number. On other models, the sight could obscure the serial number entirely, requiring arsenals to re-stamp the serial number elsewhere for easier visibility.
This Underwood Elliot Fisher M1 carbine in the NRA National Firearm Museum collection has the later ramped rear sight that partially obscures the serial number. On other models, the sight could obscure the serial number entirely, requiring arsenals to re-stamp the serial number elsewhere for easier visibility.

Most of the M1 carbines seen today have gone through extensive post-war arsenal overhauls. This resulted in many of the original factory parts being replaced by later pattern components, particularly the ramped rear sight and the "Type 3" barrel band with the integral bayonet lug. However, the re-stamped serial number wasn't standardized across all carbine rebuilds, so just because a particular carbine might only have one serial number stamp doesn't mean it hasn't gone through the rebuild process.

Additionally, the M1 Garands in U.S. military service underwent extensive rebuilding in the years following World War II, and there's a wealth of information on the markings and indicators found in rebuilt M1s. Bruce Canfield has a great overview in his story, "M1 Garand Rebuilds: History & Markings."


Latest

Aiming
Aiming

The Fire Control Sequence: 3 Steps to Perfect Round Placement

If you want to hit your target, you need three things: a gun, a target and a method by which to hit that target with that gun. Shooting well is the result of a specific process.

Why Does the .44 Special Keep Hanging On?

What is it about the .44 Special cartridge that makes it, well, special?

CAA USA Under New Ownership, Consolidation of Manufacturing

CAA USA has been acquired by Plastimold Products, owners of META Tactical, unifying all three brands and their manufacturing capabilities.

A "Shot Heard 'Round the World" Rings Out in Karnes County

As America celebrates its 250th anniversary, communities across the nation are reflecting on the people and principles that have preserved our freedoms for generations. On Saturday, June 27, the Karnes County Friends of NRA did exactly that.

Behind Winchester's New Supreme Long Range Ammunition

For 2026, Winchester Ammunition took a big step forward in its ammo offerings with Supreme Long Range. Unlike previous offerings from the company, this purpose-built long-range hunting and shooting line required the company to invest in an entirely new projectile design: the BC Max bullet.

New For 2026: Magnum Research Suppressor-Ready Desert Eagle .50

With the growing popularity of suppressors, Magnum Research is bringing its iconic .50-caliber Desert Eagle pistol up to date with a suppressor-ready, threaded-barrel version.

Interests



Get the best of American Rifleman delivered to your inbox.