U.S. Carbine Caliber .30, M1, M2, and M3 U.S. Carbine Caliber .30, M1, M2, and M3

ABOVE: Circa 1950, an Air Force officer with his modernized version of the M2 carbine featured an in-line stock, raised sights, muzzle brake and bipod.

Most readers of SAR are familiar with the current U.S. military issue M4 carbine, but some may not know why it was designated as the M4. This article is a brief history of the M4’s predecessors.

In 1938, as a result of numerous surveys of the U.S. Army Field Forces, the Chief of Infantry outlined to the Adjutant General, and the Chief of Ordnance, certain weapons requirements of the infantry. In these requirements he stated that the advisability of equipping ammunition carriers, machine gun crew members, mortar crews and administrative personnel, with a light-weight shoulder weapon. The document dated September, 1938 requested consideration by the Office of the Chief of Ordnance. An evaluation of the Chief of Infantry’s request was made in November of 1938. The use of a new light rifle was not favorably considered at that time.

With the German invasion of Poland in 1939, the Chief of Infantry resubmitted his request for the development of a light rifle. This time the suggestion was considered and by June of 1940 the War Department acted to initiate a weapon development program. By directive 00 474.5/120 from the U.S. Secretary of War, the Chief of Ordnance was ordered to undertake the development, testing, and selection of a light rifle. It was estimated that 500,000 of the new light rifles would be needed, which turned out to be a very conservative figure.

A U.S. Army armorer inspects a stack of well-used M1 carbines.

The Chief of Infantry submitted general requirements for the proposed weapon, these were:

Not less than .27 caliber.
Not more than 5-pound weight with a loaded twenty round magazine.
Effective range not less than 300 yards.
Operating system to be semiautomatic, bolt or lever action.
Five or seven round capacity, seven rounds preferred.
Fixed aperture sights, effective to 300 yards.
Ammunition to have mid-range ordinate of no more than eighteen-inches at 300 yards.
Barrel should be short.
A 1903 type sling should be used.

The Cavalry (Armored Forces) and other combat units concurred with the Infantry’s requirements. The Chief of Infantry specifically recommended that each of the following be developed for possible use:

A light semiautomatic rifle
A submachine gun type
A bolt action rifle

With the selector on an M2 carbine in the forward position (shown) the carbine fired full-automatic. The rearward position was for semiautomatic fire.

The desired characteristics for the light weight rifle were prepared by October of 1940 and were approved at an Ordnance Committee meeting. The requirements were presented to eleven manufacturers and individuals by the end of 1940 including:

The Auto-Ordnance Corporation
Colt’s Patent Fire Arms Manufacturing Company.
Hi Standard Manufacturing Company.
Johnson Automatics.
Marlin Firearms.
J.D. Peterson.
Remington Arms Company.
Savage Arms Company.
Smith & Wesson
Winchester Repeating Arms Company.

Each concern received a circular listing weapon requirements, a drawing of the new .30 carbine caliber cartridge and minimum chamber requirements. Within a few months, twenty-five corporations and individuals were invited to submit a design with testing scheduled for 8 May 1941 at Aberdeen Proving Ground. Several weapons that were submitted were immediately rejected. As a result of the preliminary testing certain changes were recommended in the original requirements. The weight was increased to 5.5 pounds and the full-automatic requirement eliminated.

The fire control components of a semiautomatic M1 (top) and the select-fire M2 carbine.

U.S. Carbine, Caliber, .30 M1

The Winchester Repeating Arms entry was the eventual winner of the light rifle trials. The Winchester carbine used a unique short-stroke tappet gas system, and was adopted as Carbine, Caliber .30, M1 in October of 1941. By the war’s end there were more carbines manufactured than any other U.S. small arm. A number of diverse companies manufactured the carbine during the war; these prime contractors were supported by hundreds of subcontractors. Many of the prime contractors involved in the carbine program had no previous gun making experience, many of them manufacturers of music boxes, automotive parts and business machinery, rallied for the war effort to manufacture 6,079,648 carbines by 1945. Although the price of the carbine varied by contractor and contract, the average cost was approximately $50 per weapon. M1 Carbine prime contractors were: Winchester, Inland (Division of General Motors), Underwood-Elliot-Fisher, National Postal Meter (A very limited number were made under the name Commercial Controls Corporation), Rock-Ola, Quality Machine and Hardware, Standard Products, Saginaw Steering Gear (Division of General Motors), International Business Machine (IBM), Irwin-Pederson Arms Company (their contract was taken over by Saginaw).

Years manufactured: M1:1941-1945 (M2: 1945 only)
Magazine capacity: fifteen and thirty round box
Caliber: .30 carbine, 110 grain round nose bullet, 1,970 fps
Cyclic rate (M2 only): 750-775 rounds per minute
Operation: gas operated, closed locked bolt, select-fire (M2)
Weight: 5.2 lbs. (M1A1 model 5.5 lbs.)
Barrel length: 18 inches
Overall length: 35.75 inches (M1A1 length, stock folded 25.75 inches; stock extended 35.75 inches)

M1 Recoil Check, designed to help control muzzle rise on the M2 in the full-automatic mode of fire. The device was secured to the barrel with a clamp.

U.S. Carbine, Caliber, .30 M1A1

To make the carbine more compact for paratrooper use, the M1 carbine was fitted with a side-folding metal buttstock and wooden pistol grip. Carbines in this configuration were designated as the M1A1. With the stock in a folded position the overall length was reduced to 25.75 inches. With the stock unfolded, the overall length of the M1A1 was the same as an M1 carbine. The M1A1 was specifically designed for airborne troops and the action was the same as an M1 carbine. The only manufacturer of the M1A1 was the Inland Division. A total of 140,591 were manufactured from 1942-45. There were no M1A1 carbines originally manufactured as select-fire M2s.

Cartridge, Carbine, Caliber .30

Winchester had also developed a new mid-range cartridge to be used in the new “light rifle.” The cartridge was designated as, Cartridge, Carbine, Caliber .30 M1 and was approved as Standard on 30 September 1941. The Ordnance Department awarded contracts to the Western Cartridge Company, Winchester Repeating Arms, Remington Arms Company, Lake City Ordnance Plant and the Kings Mills Ordnance Plant. While corrosive primers were used in World War II .30-06 and .45 ACP caliber U.S. service cartridges, the .30 caliber carbine rounds all utilized non-corrosive primers. The decision to use non-corrosive primers greatly extended the service life of the carbine’s barrel.

An early M1 and folding stock M1A1 “paratrooper” carbine.

The original configuration of the .30 caliber carbine cartridge was changed early in 1942. The original .30 caliber 110-grain projectile had a cup style base, which tests had shown was unstable during firing, and would often leave a ring of gilding metal in the forward end of the chamber. A new flat base 110-grain projectile was designed to eliminate the problem. The type of powder used in the carbine cartridge was also changed. The original DuPont powder proved to be too bulky for the small case. To achieve a higher projectile velocity a new DuPont powder was introduced. The new powder increased the carbine’s muzzle velocity to 1,970 feet per second and raised the chamber pressure to 40,000 psi.

In September of 1944, the nomenclature of the .30 carbine round was changed to Cartridge, Ball, Carbine, Caliber .30 M1. The change, adding the word “ball,” was to avoid confusion with the newly adopted tracer and grenade launching cartridges developed for the carbine.

The early characteristics of the new cartridge were:
Bullet weight: 110 grains.
Charge weight: 14.5 grains of IMR 4227
Primer: Winchester No. 116
Pressure: 31,000 psi
Muzzle velocity 1,860 feet per second.

The new specifications for the improved carbine cartridge were:
Bullet weight; 110 grains
Charge: DuPont 4809 or Hercules 3950.8B (alternate)
Primer: commercial non-corrosive
Pressure: 40,000 psi
Muzzle velocity 1,970 feet
per second

In September of 1944, the nomenclature of the .30 carbine round was changed to Cartridge, Ball, Carbine, Caliber .30 M1. The change, adding the word “ball”, was to avoid confusion with the newly adopted tracer and grenade launching cartridges developed for the carbine.

Very early box of carbine ammunition: note that the nomenclature is Caliber .30 M1 Short Rifle M-1, so that it would not be confused with M1 Garand ammo. (Courtesy of John M. Miller)

U.S. Carbine, Caliber .30, M2

The original 1940 requirements for the carbine included a select-fire feature. In order to get a new weapon developed quickly, this requirement was dropped. The select-fire M2 would not be fully developed and subsequently adopted until the fall, 1944.

Early in 1944, the Inland Division began to develop a method to convert the M1 carbine into a select-fire weapon. Two Inland engineers, Paul Hamisch and Frederick Sampson, designed a conversion that required only a few new parts along with minimum changes to the weapon’s original design. The experimental select-fire M1 carbine was designated as the T4. After extensive testing of the modified carbine, the weapon was recommended for adoption as the Carbine Caliber .30, M2 in September of 1944 and was adopted as Standard in October 1944. Subsequently, the M1 and M1A1 carbines were reclassified as Limited Standard. By the time the weapon began getting into the hands of the troops in the field the war in Europe was almost over. The M2 carbine saw little combat use in World War II.

The firepower of the M1 carbine was greatly increased with the introduction of the select-fire M2 version. Like a submachine gun, the full-automatic M2 was effective for close-in combat situations and street fighting. The M2 could also be used effectively in the semiautomatic mode at longer ranges, where a pistol caliber submachine gun could not. Original M2s were only manufactured by Inland (199,500 M2 carbines), and Winchester (17,500 M2 carbines). Early Winchester M2s were marked by over-stamping the numeral 1 on the front of the receiver with a number 2. All later manufacture M2s were factory roll-marked “M2.” Original Inland and Winchester M2s all have high serial numbers over 6,000,000. There were a few very early Inland M2s manufactured with six digit serial numbers beginning with zero. Original manufacture M2 carbines were usually factory fitted with late style features, such as the adjustable style rear sight, improved safety lever and the barrel band with the bayonet lug.

Select-fire M2 carbine with 30-round magazine and muzzle brake. The cyclic rate was approximately 750 rounds per minute. RIGHT: M3 carbine with late production M3 sniper scope. (U.S. Marine Corps National Museum)

The M2’s published cyclic rate was from 750 to 775 rounds per minute. A large capacity 30-round magazine was introduced to keep up with the M2’s high rate of fire. The carbine’s light weight together with its relatively fast cyclic rate made it somewhat difficult to control in the full-auto mode of fire. One item designed specifically for controlling muzzle rise on the M2 carbine was the M1 recoil check or muzzle brake.

Some M1 carbines were converted to the M2 configuration by using the “Kit, Conversion T17.” This kit contained all the parts needed for unit armorers to upgrade their M1 carbines to the M2 status. Many existing M1s that were converted were remarked by over-stamping the number 1 with a 2 on the receiver by hand. After World War II ended in Europe, FN Belgium was contracted to inspect and rebuild carbines, and convert some of them to the M2 configuration. The FN program was completed in 1946. Virtually all weapons returned to the U.S. were rebuilt before being placed into long term storage after the war. During the Ordnance Department rebuilding programs, a large number of M1 carbines were also rebuilt to M2 specifications. Just a few years later, the M2 carbine would see its share of combat action in the Korean Conflict.

U.S. Carbine, Caliber, .30 M3

Based on scientific experiments begun in the 1930s, the “Sniperscope, T120” was developed in late 1943. Electronic devices could distinguish objects illuminated by infrared light and make them visible in a telescope. A 6-volt light with an infrared filter mounted under the stock provided invisible light to illuminate an area up to a distance of 400 feet. This combination of a light source and telescope using infrared light became the first practical night vision sight. A handle and a switch for the light were mounted on the stock. Both the telescope and the light source got their power from a heavy, lead-acid wet cell battery carried in a canvas pack.

Before the M3 carbine and M1 sniperscope were type-classified, they were known as the T3 and T120, respectively. The M3 was a carbine fitted with a mount designed to accept an infrared sight for use at night. It was initially used with the M1 sniperscope, an active infrared sight, and saw action in 1945 with the Army during the invasion of Okinawa. An improved M2 sniperscope extended the effective nighttime range of the M3 carbine out to 100 yards. Both the M1 and M2 sniperscopes had the light source located below the stock.

Select-fire M2 carbine with 30-round magazine and muzzle brake. The cyclic rate was approximately 750 rounds per minute. RIGHT: M3 carbine with late production M3 sniper scope. (U.S. Marine Corps National Museum)

The original T-3 version of the carbine was complicated, requiring a number of unique parts to mount the sniperscope. Eventually it was decided to design a simple kit that would enable a standard M1 or M2 carbine to be easily converted to use night vision sights in the field. The special mounting parts would be included with the sight sets. A new flash hider was added to conceal the user’s position. Mass production of the improved infrared night vision system began in 1950 with the “20,000 volt Set No. 1.” This could be mounted on any M1 or M2 carbine, making it an “M3” Carbine. The M3 sniperscope had a large active infrared spotlight mounted on top of the scope body itself, allowing its use with the operator in a prone position. The revised M3 had an effective range of around 125 yards. The improvements in this system included better electronics, resulting in better vision, but were still limited. Fog and rain further reduced the weapon’s effective range. Heavy weight and short battery life remained major shortcomings.

The U.S. M1 and M2 carbines remained in U.S. Army service until the M14 was accepted as their standard weapon in 1957. However, the service life of the carbine had not ended. The U.S. Air Force and Navy still issued them, and the carbine would see more action in the Vietnam War. Large numbers of carbines were provided to many allies and some former enemies as military aid.