The U.S. Caliber .30 Carbines


Parts, Variations, & Markings

The Basics Here
The U.S. Caliber .30 CarbinesThe Carbine ManufacturersThe Barrel ManufacturersParts, Variations & Markings
Carbine NomenclatureThe Serial NumbersThe Stocks & HandguardsPost WWII Ordnance Operations

The information presented here is meant to be a basic introduction, not a reference work.

Redesigned Parts

The U.S. Caliber .30 Carbines consisted of 56-81 parts, depending on the model and time of manufacture.

U.S. Ordnance redesigned a number of parts over the course of production and after WWII, several parts more than once. Most of these changes were to improve reliability and/or function, manufacture time, and/or cost. None of the changes were so critical as to merit a massive recall. A few of these changes were important enough to merit replacing the earlier part with the later variant when the carbine could be inspected by U.S. Ordnance personnel. For most carbines this wouldn't happen until after the end of the war (see below).

Two of the unique things about the U.S. GI M1 Carbines are almost all of the parts are backwards and forwards compatible regardless of whatever change was made, and, all of the parts are interchangeable from one carbine to another without requiring individual fitting.

Generally, the earlier parts tend to be less common and more expensive. The later parts generally tend to be more common and less expensive. A few parts manufactured as replacements can still be found in new unissued condition. Some parts were contracted to be manufactured as late as 1967 (e.g. M2 stock, M2 handguard, cast recoil plates).

A Few Examples of Parts that were Redesigned during WWII

Barrel Bands

Three Variations

(The barrel band with bayonet lug was used late 1944 and later. Bayonets were being manufactured by the end of WWII but none have been seen, so far, on the carbines used during WWII)

1st style Barrel Band

2nd style Barrel Band

3rd style Barrel Band with bayonet lug


More than Six Variations

(Angled face above chamber on later designs deflects spent casings away from chamber)

Slide w/ straight face (top) - Slide with angled face (bottom)

Magazine Catch

Six Variations

(M on Magazine Catch face means "Modified". Indicates the rail thickness was reduced to provide better operation and has nothing to do with the mfg)

One of several different
early style mag catches

Later design with Modified
rail thickness

Later design Modified mag catch
with support arm

The arm to support the extra weight
of a 30 round magazine


Four Variations

(The first three were push buttons, the fourth was a rotary to eliminate pushing the wrong button)

Push Safety

Rotary Safety

Rear Sight

Three Variations


Adjustable Rear Sight

Adjustable Rear Sight

U.S. Army Ordnance Primary Contractor and Subcontractor Part Markings

A "primary contractor" was a company that produced the entire carbine. None of the primary contractors produced all of the parts necessary to produce their carbines. Hundreds of subcontractors filled this role. On parts that were marked, primary contractors who manufactured the part used their mark only (refer manufacturer marks under each manufacturer), subcontractors who manufactured the part placed their assigned mark and the mark of the primary contractor they made the part for.

At first glance, these markings may appear to be pretty simple and straight forward. Sometimes they are, sometimes they're not. A few examples:

A Few Words of Caution

Examples of Subcontractor Markings

Front sight

stamped SN

Front sight manufactured by Super Metal Manufacturing of North Bergen, NJ for National Postal Meter

Rear sight

stamped PI

Adjustable rear sight manufactured by Packard Mfg. Corp. of Indianapolis for Inland

Barrel Band

stamped diamond containing D

Barrel Band w/ Bayonet Lug manufactured by Donaldson Co., Inc. of St. Paul, MN as a replacement part for all carbines


stamped UN

Flat Bolt (right lug face) manufactured by Union Switch & Signal of Swissvale, PA for National Postal Meter


stamped block containing RMC

Handguard manufactured by Rock-Ola Manufacturing Co.
(the number was added later by a police department)

Recoil Plate

One example of the variety of places markings may be found, on the Recoil Plate alone

Manufactured by Lyman Gun Sight Company of
Middlefield, CT, for National Postal Meter

Manufactured by
Rock-Ola Manufacturing Co.

Manufactured by
Winchester Repeating Arms

Manufactured by Parker Mfg Co. of Worcester,MA
for IBM

Manufactured by Wadsworth Watch Case Co. of Dayton, KY
for Inland

Manufactured by Garden City Plating
as a replacement part

Manufactured by Dayton Mold Co. of Dayton, OH
for Inland

Manufactured by H.B. Rouse & Co. of Chicago, IL
for Quality Hardware Mfg

Post WWII Cast Recoil Plate marked E2
unknown manufacturer

If you'd like to see examples of WWII M1 Carbines with a breakdown of their parts and manufacturers, CLICK HERE.

If you are interested in further details you may wish to check out the page devoted to books. War Baby! by Larry Ruth identifies many of the markings and the manufacturers they represented along with carbines they were used on. U.S. M1 Carbines Wartime Production by Craig Riesch has quick reference charts that identify the part variations and the markings used by each manufacturer.

Things To Keep in Mind

Where and Who to turn to for More Information and Further Assistance

I wish I could help everyone, but with over 6 million U.S. Carbines and almost 1 million post war commercial carbines one person can't handle all the requests for assistance. However, there are a number of resources available that can answer any question you might have, including groups of knowledgeable collectors and shooters on discussion forums. The internet is ripe with experts on almost every topic, so you would be wise to get opinions from more than just one person.

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