M1 Carbines Incorporated

.30 Caliber Carbine

Basic Nomenclature

Introduction ***Please Read This First***

The purpose of this page is to familiarize you with the basic parts that make up a .30 Caliber Carbine.

During and after WWII U.S. Army Ordnance changed the specifications for some of the carbine parts. Sometimes more than once. The reason for the changes included improved function and/or reliability, and sometimes cost. It is not possible to cover all of the part design changes U.S. Army Ordnance made and/or all of the manufacturing variations GI contractors/subcontractors made or used at various points in time. This page is devoted to basic nomenclature, not part variations. A few variations are included below as they are commonly encountered.

For part details and manufacturer variations refer to War Baby! The The U.S. Caliber .30 Carbine by Larry Ruth.


The U.S. .30 Caliber Carbine M1 consists of five major part groups.
  • Barrel Group
  • Receiver Group
  • Stock Group
  • Bolt Group
  • Trigger Housing Group

Below Illustrations adapted from:

TM 9-1276
Technical Manual
Caliber .30 Carbines
M1, M1A1, M2, and M3

Note: Parts followed by an * are parts that may have U.S. Army Ordnance contractor/subcontractor markings

Barrel Group & Receiver Group


  • Barrel*
  • Front Sight*
  • Front Sight Key
  • Front Sight Pin
  • Barrel Band*
  • Bayonet Lug* (later design)
  • Gas Piston*
  • Gas Piston Nut
  • Operating Slide Spring
  • Operating Slide Spring Guide*
  • Receiver*
  • Rear Sight*
    (adjustable was later design)
  • Slide*
  • Slide Stop
  • Slide Stop Spring


Stock Group


  • Stock*
  • Handguard*
  • Front Band Spring
  • Recoil Plate*
  • Recoil Plate Screw*
  • Recoil Plate Escutcheon Nut
  • Buttplate*
  • Buttplate Screw

Bolt Group


  • Bolt* (initially flat, round designed
    for M2 & works on M1)
  • Ejector & Spring
  • Extractor*
  • Extractor Plunger
  • Extractor Plunger Spring
  • Firing Pin*

Trigger Group


  • Trigger Housing*
  • Trigger Housing Pin
  • Hammer*
  • Hammer Spring
  • Hammer Plunger*
  • Hammer Pin
  • Sear*
  • Sear Spring
  • Trigger*
  • Trigger Spring
  • Safety*
  • Magazine Catch & Safety-
    Plungers and Spring
  • Magazine Catch*
  • Magazine Catch-
    Plunger and Spring

Magazine - 15 round


  • Body*
  • Follower
  • Spring
  • Base Plate
Markings are usually on the rear of the
magazine below the retaining lugs.

Originally, only the 30 round magazine
had a follower that would hold the bolt
back and slide open after the last shot.