The History Behind the Great M1A1 Carbine

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The M1Carbine was the most widely produced US infantry weapon of World War II; 6,221,220 being manufactured between late 1941 and mid-1945. By comparison, during the War, there were 4,028,375 M1 Garands produced, though additional M1 rifles had been produced prior to US entry into the war. The M1 Carbine was light and handy, was a semi-auto, had a 15-round magazine, and was easy to shoot. Though initially intended as a compromise between the infantry rifle and the 1911 pistol for troops who were not front line infantrymen, a substantial number of M1 Carbines would see front line combat.

There were strong and varying opinions on the lethality of the M1 Carbine’s 110-grain bullet with a muzzle velocity of 1,990 feet. It was not as lethal nor had the stopping power of the M1 Garand’s .30-06 cartridge. Some felt that at close range the .45 ACP was a better stopper. However, it certainly outranged the 1911A1 pistol’s .45 ACP round. It could be fired more accurately than the pistol or the M3 SMG at ranges past 50 yards (though the M1 Thompson SMG was effective at longer ranges) and had a magazine capacity of 15 rounds in detachable box magazines.

Based on reading various accounts of infantry weapon performance in World War II, subjectively, it seems to me that soldiers in the European Theater tended to be more critical of the M1 carbine than soldiers in the Pacific Theater of operations. This may be attributable to longer ranges and larger enemy soldiers in the European Theater compared to smaller enemy encountered at closer ranges in jungle conditions, often in mass attacks where rapid magazine changes of the M1 Carbine were appreciated.

There was also the bugaboo of troops in the Pacific that the “Twang!” of a Garand clip being ejected alerted the Japanese to attack. Although this was primarily a myth, it may have made the quieter M1 Carbine magazine change appealing. A friend and I once did a test with one of us shooting an M1 Garand and the other standing at various distances, and, I must admit, we could hear the empty clip being ejected to 25 yards or more. But, in combat, without ear protection and with multiple weapons firing, it would have been more difficult to identify an individual rifle ejecting its clip.

Modifciation Request

Prior to introduction of the M1 Carbine, US Airborne troops had normally been armed with the M1 Garand or M1 Thompson SMG. Both weapons were formidable but were bulky and heavy for a soldier that exited an airplane to fight. Once the M1 carbine became available, it was used by some airborne and glider troops. However, during the spring of 1942, interest was expressed in a folding stock version of the M1 Carbine specifically for airborne troops. Winchester, Springfield Armory, and Inland Manufacturing worked together on the project, with a design being submitted by an Inland engineer in March, 1942, that allowed the stock to be folded or unfolded, yet still allowed the carbine to fire in either stock position.

Approved on 12 May 1942, the carbines with this stock were designated the M1A1. For easier handling with the folding stock, a pistol grip was incorporated, but all other carbine parts remained the same as on standard M1 Carbines. While, the small tubular oiler issued with the M1 Carbine was designed to fit inside a slot in the stock and act as a rear swivel for the sling, on the M1A1, the oiler snapped into a bracket behind the cheek rest of the M1A1 Carbine. The rear sling swivel on the M1A1 was at the base of the stock’s pistol grip.

The Inland Division of General Motors produced all M1A1 Carbines. This would prove an advantage for the airborne troops, as Inland production carbines are generally considered the best among the 10 manufacturers of the M1 Carbine. Between 1942 and 1945, 140,591 M1A1 Carbines were manufactured. Two production runs took place; the first between October 1942 and October 1943, and the second between May, 1944, and December, 1944. Each run was of around 70,000 M1A1 Carbines. The difference in carbines from the two production runs will be discussed below.

M1A1 Into Action

The M1 Carbine never replaced all other infantry weapons in an airborne division. For example, in October 1942, the Table of Organization and Equipment (TO&E) of an airborne division with a strength of 8,203 personnel called for 3,328 M1 Carbines. A substantial number of M1 Garands, M1 Thompsons, and a few M1903 Springfields (for grenade launching) remained on issue. Note, too, that when that 1942 TO&E was created the M1A1 carbine was not yet available so fixed stock carbines were used. For a better grasp of the number of M1A1 Carbines that would have been in issue among airborne troops the TO&E for a 583-man parachute infantry battalion in August 1944 shows two .45 caliber pistols, 18 .45 Thompson SMGs, 310 M1A1 Carbines, and 280 M1 Garands. Reportedly, the first combat use of the M1A1 was by paratroopers of the 82nd Airborne Division in July 1943, during “Operation Husky,” the jump on Sicily.

Although some paratroopers jumped with their M1A1 Carbines tucked into their parachute harness, the intent was that a scabbard—sort of a large pistol holster, which could be strapped to the paratrooper’s leg—would be used to protect the carbine during the jump. Before development of this scabbard, paratroopers jumped with their disassembled M1 Garand or M1 Carbine in a larger padded jump bag. This bag was still employed for M1A1 Carbines if the leg holster was not available. Some accounts from 11th Airborne Division in the Pacific indicate that they did not receive the leg holster during the War.

As the M1A1 basically used standard production Inland carbines and just dropped them into the paratrooper stock, standard features were retained. As a result, the first production run of M1A1 Carbines employed a flip-up “L”-sight, with peepholes marked for 100 and 300 yards. These sights were notorious for being off in windage and were virtually impossible to adjust as they were pinned in place. Early production M1 carbines also used a cross bolt button safety, located just behind the magazine release button. Finally, early carbines did not have a bayonet lug. Instead, the carbines were issued with the M3 Trench Knife, easily recognizable for its stacked-leather-washer handle and crossguard that bent forward. Many World War photos of paratroopers show the M3 Trench Knife strapped to their legs.

In the later production run of M1A1 Carbines, the flip-up sight was replaced with an adjustable rear sight that allowed easy adjustment for windage. Because some troops, especially among Marines issued the M1 Carbine, found that magazines could be accidentally ejected in combat by pushing the release button instead of the safety, a lever safety was developed and added to later production carbines including M1A1s. Finally, a bayonet lug was added and the M4 bayonet was developed.

The M4 is basically the M3 Trench Knife altered to affix to the bayonet lug. About half of M1A1 carbines were produced with early features and about half with some or, all, later features. However, after World War II, many early production carbines were “upgraded” by retrofitting to the later type. When the select fire M2 Carbine was developed, 30-round magazines were issued with it. The 30-round magazines would work in standard M1 or M1A1 Carbines, but the magazine catch was not intended for the heavier loaded 30-round magazines. As a result, post-war retrofitting also often included a stronger magazine catch. While mentioning magazines it is worth noting that the 15-round M1 Carbine magazines as originally developed were fragile and were not viewed as viable for long term use. Airborne troops using the M1A1 would normally get fresh magazines before an operation and whenever resupply was available would switch out old magazines for new.

Win Wars

Winning the war, not preserving collectible small arms, was the mission of the US Ordnance Corps and other portions of the armed forces during World War II. As a result, finding M1A1 Carbines that remain as originally issued in World War II has become difficult and expensive. The popularity of the TV series Band of Brothers only increased the demand for M1A1 Carbines. For the collector attempting to add an original M1A1 to his collection, he must first avoid recent reproductions and fakes. To begin, ALL World War II M1A1 Carbines were manufactured by Inland. It is possible that post-World War II refurbished carbines will be found with M1 Carbines from other manufacturers inserted into an M1A1 stock. These are not authentic World War II M1A1s, though they might have seen use by US troops later. There are various ways of telling an original World War II M1A1 stock. One of the most obvious is the presence of the casting number, normally “B257614*,” followed by a one- or two-digit number inside the butt plate.

I find some post-World War II refurbished M1A1 Carbines interesting. They have the upgraded features such as better sights, but they are still original Inland production carbines in original M1A1 stocks. For example, my late model M1A1 shown in this article was manufactured by the Inland Manufacturing Division of General Motors and fitted with an original GI paratrooper M1A1 folding stock. Its Inland Division barrel is dated “4-44,” and it has “RIA” (Rock Island Armory) blade front and “I.R.Co.” (Inland) adjustable peep rear sights, “SI” (Inland) marked Type III barrel band, round bolt, switch safety, and “M” marked magazine catch (indicating a catch designed for 30-round magazines).

The paratrooper stock has a four-rivet handguard, low wood forearm, “RIA/ EB” boxed cartouche on the left side below the receiver, circled block “P” on the grip, and folding wire buttstock with leather cheekpiece and checkered steel buttplate marked “B257614.” The cartouche and “P” on the grip are indicative of a post-war refurbishment/upgrade. I find the fact that this M1A1 was used enough to merit refurbishment and that it saw continued service as features that make it more attractive. Just as a sidenote: the M1 Carbine I keep as a house or car gun is an Inland fixed stock model that was upgraded after the War.

Refurbished M1A1 Carbines may well have originally “jumped” with paratroopers on “D-Day,” “Market Garden,” or “Varsity” then undergone modernization in case troops of the post-war airborne had to go into combat. Some may have seen action in Korea. In fact, the M1A1 was still being used by some US troops in Vietnam. The folding stock allowed helicopter crewmen to tuck an M1A1 into the cockpit, though they often had to trade with Vietnamese troops to acquire it. M1A1 carbines were also popular with US advisors to Vietnamese units who had M1 Carbines. Some advisers stuck an M2 Carbine with cut down barrel into the M1A1 stock, while others used a standard M1A1 with cut down barrel.

The M1A1 remained popular with airborne units of US allies. In Indochina, French Legion and Colonial Paratroops used the M1A1, with some captured at Dien Bien Phu turning up in Viet Cong hands during the Vietnam War. The M1A1 was popular with French Paras who made many combat jumps in Indochina because they could carry more .30 M1 Carbine rounds.

Author's M1A1 Carbines

I have two M1A1 Carbines. One retains the early features, though there is an anomaly, as the serial number of the carbine and its barrel markings put it right at the end of the first batch of M1A1 carbines when the stocks would have had what is known as a “High Wood” slot for the slide cut, while the stock has the “Low Wood” of the second batch of M1A1 Carbines. Otherwise, all parts conform to the earlier type of M1A1. It is used in this article to illustrate some aspects of the M1A1. Sorting out all of the intricacies of an “authentic” World War II M1A1 requires much more space than available in this article, but at the end I’ll recommend a couple of books that will help.

To wrap up this article I thought I should shoot my refurbished M1A1, as it has the better sights. As much as I like the M1A1 for its association with America’s first paratroopers and its handiness, I shoot a fixed stock M1 Carbine better. The M1A1 butt plate doesn’t rest as comfortably on my shoulder making my groups at 100 yards about two inches larger than with a fixed stock gun. Therefore, I decided to shoot 50-yard groups with my M1A1 for this article—you know, fighting clear of the drop zone distance! 

Using M1 Carbine ammo of three types, the groups were between 17⁄8 and 25⁄8 inches. My friend Tim Mullin, who was shooting with me, had brought his CMP 1911A1 pistol that he had recently received and suggested an interesting test as World War II paratroopers were often armed with both a 1911 pistol and an M1A1 Carbine and for some the M1A1 had replaced the 1911. He decided to fire comparative groups representing two situations: first, a meeting engagement at seven yards in which he would fire both weapons quickly, starting with the safety engaged; and second, aimed, slower fire at 50-yards off hand. As was to be expected, the groups fired at seven-yards were substantially better with the M1A1; however, at 50 yards, the difference in group size between the two weapons was less than an inch, though the M1A1 grouped better. To some extent this was a reflection of the fact that Tim shoots handguns a lot at ranges between 25 and 50 yards.

Still, the test also points up that fact that the mistake that was often made in World War II and Korea was in comparing the M1/M1A1 Carbine with the Garand rather than with the 1911. The Carbine was intended to give troops who would have normally been armed with a 1911 pistol a more effective weapon yet one that was handier and easier to carry than an M1 Garand for support troops, engineers, crew-served weapons teams, and paratroopers. In the case of the airborne troops, enough of them remained armed with the Garand or BAR to hit harder and further. The M1A1 gave those paratroopers who jumped with it, a weapon that would shoot faster and longer without reloading.

Tactically, airborne troops were meant to carry out raids to seize critical objectives such as bridges and to hold them only for a limited amount of time. However, sometimes paratroopers found themselves waiting longer for the armor or leg infantry to reach them than expected. In those cases, the M1A1’s limitations in range and striking power were offset by the greater amount of ammo in magazines and bandoliers that the individual paratrooper could carry. For example, 300 rounds of .30-Carbine ammo would weigh 8.4 pounds, while 300 rounds of .30-06 ammo would weigh 17.3 pounds. The M1A1 was, indeed, a compromise weapon, but remains an iconic one and a very cool one! 

ORIGINAL G.I. INLAND M1A1 CARBINE SPECIFICATIONS

• Caliber: .30 Carbine
• Action: Semi-Auto, Short-Stroke Gas Piston, Rotating Bolt
• Overall Length: 35.6 in. (stock extended); 25.5 in. (stock folded)
• Barrel Length: 18 in.
• Weight: 6.2 lbs.
• Magazine Capacity: 15 rounds
• Sights: Early: Rear L-Shaped Flip-Up, Later: Adjustable; Front: Post

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