Historical Firearms
Welcome to Historical Firearms, a site that looks at the history, development and use of firearms, as well as wider military history
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Converting the M1 Carbine Into An AR-15

In August 1969, Thomas Donnell, of East St. Louis, Illinois filed an interesting patent - for converting a M1 Carbine into an AR-15. Donnell explained the purpose behind the conversion in the patent, saying that he aimed to convert an M1 to give it the “overall asthetic appearance similar to the military M-16 rifle or the civilian version of such rifle, namely the AR- rifle.”

He noted that:

“The system which may include components packaged in the form of a kit for the firearm enthusiast to make the conversion on his own, generally uses the barrel and receiver assembly of the M-1 carbine in combination with the components provided by the present invention. A stock is provided which is adapted to receive the barrel and receiver assembly of the M-1 carbine and an upper hand guard will fit over a portion of the barrel and mate with a portion of the stock.”

Along with a new stock the kit would also include an “upper hand grip, front sight and similar accessories” so that the M1 carbine had “an overall appearance which resembles the M-16 rifle.” Donnell even went so far as to design an ‘extension block’ to make the M1′s .30 calibre magazine look like a 20-round 5.56x45mm M16 magazine. Only the M1′s barrel assembly and the receiver remained once the conversion was done. 

Donnell even takes the time to discuss the psychology behind the desire for a conversion saying:

“Gun styles are often affected by the style of gun which is employed by military establishments… In recent years, the military M-l6 rifle has received widespread attention. In fact, there is at least one civilian version of a rifle based on the M-l6, namely the AR-lS rifle, and which has substantially the same outer appearance as the military M-16 rifle.”

He continues explaining that AR-15s are complex and expensive to manufacture and buy therefore their is a necessity to create rifles that copy the AR’s aesthetic. At the time surplus M1 Carbines were certainly cheaper than a brand new AR-15 from Colt. 

Donnell’s kit design is certainly ingenious but I’ve not been able to find any examples of the conversion so it is unlikely it ever made it to market. Interestingly, Donnell’s patent has, however, been cited by subsequent patents from companies including Colt, Beretta and Mossberg.

Source: 

‘Firearm Conversion System’, T. Donnell, 12 Oct. 1971, US #3611607, (source)

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Winchester 9mm M1 Carbine Prototype

The collection of the Cody Firearms Museum holds an interesting 9x19mm conversion of an M1 Carbine. Little is known about the prototype carbine, its origins or its intended purpose. Herbert Houze, former curator of the Cody Firearms Museum, suggests that it was developed after World War Two by one of Winchester’s engineers, Harry H. Sefried.

The 9mm M1 Carbine has a proprietary magazine which is smaller than the standard 15 round .30 Carbine magazine, although it appears about the same length suggesting a similar capacity. It appears that the carbine’s action has been shortened slightly, it is possible to make out a cut in the stock just in line with the weapon’s charging handle. The 9mm carbine’s length is reportedly 34.25 inches compared with a standard M1 which was 35.6 inches long.

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The seam in the carbine’s stock can be seen just above the magazine (source)

It is unclear if the 9mm carbine retains the M1′s short-stroke (tappet) gas system but it seems unlikely that it has been converted to a simpler blowback action as this would likely require a redesign of the M1′s rotating bolt. The magazine pattern appears to be similar to that used by Winchester in a number of other designs in various calibres. 

Sadly, I’ve been unable to find any evidence that Sefried patented his conversion and Winchester never offered the conversion commercially. In the mid to late 1940s Harry Sefreid also developed an experimental Winchester Model 1905 semi-automatic commercial rifle that was rechambered in .45 ACP. Houze believes these experimental projects were undertaken by Sefried as side projects. Today, both experimental prototypes are held by the Cody Firearms Museum at the Buffalo Bill Centre of the West in Wyoming. 

Sources:

Images: 1 2


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In Action: M1 Carbine & M1 Garand

The photograph above shows two infantrymen from the 37th Infantry Division during street fighting in Manilla in February 1945. The men are negotiating some Japanese barbed wire. The soldier in the foreground has an M1 Carbine fitted with an M8 Rifle Grenade Launcher, while the man next to him has the ubiquitous M1 Garand

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M8 attached to an M1 Carbine (source)

Specially developed for the M1 Carbine, the M8 launcher was fitted over the muzzle with a hinged locking piece which closed over the barrel behind the front sight. A wingnut was then tightened to secure it in place. Several versions of the M8 were developed during the course of the war with a number of simplifications made for manufacture. Just under 400,000 M8s were made between 1943 and 1945. Like the M1 Garand’s M7, the M8 used a special high-powered projectile-less launcher round, the M6 grenade cartridge. These could be used to launch a variety of high explosive, smoke and signal grenades. The M8 continued in service and saw action during the Korean War. 

Sources:

Images: 1 2 3

Video of troops training with M8 Rifle Grenade Launchers (source)


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Call of Duty: WWII Trailer Breakdown

Call of Duty returns to its roots as Activision/Sledgehammer unveil the first trailer for the next installment of the franchise. Following the trend set by their main rival, Battlefield 1, Call of Duty are again looking to the past rather than the present and future.

From the limited information available the game seems to focus on a Texas-farm boy thrust into the Allied invasion of Europe as part of a platoon of the 1st Infantry Division. This isn’t the first time Call of Duty has focused on the 1st with 2005′s Call of Duty 2: Big Red One revolving around the unit. The trailer takes us from the D-Day landings to the fighting inshore in the dense hedgerows of the Bocage behind the beaches.

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The trailer features an extended sequence showing the protagonist coming ashore on Omaha Beach. The scene is reminiscent of the opening of Saving Private Ryan, Medal of Honour European Assault and of course Call of Duty 3.

Lets breakdown the weapons that appear in the trailer. Naturally many of the US infantry weapons you would expect to see are featured. Including M1 Garands, M1911A1 pistols, M1918A2 BARs and a heavy focus on M3 submachine guns. While the M1 Carbine isn’t seen clearly in this short trailer it features in some of the publicity images released. Interestingly the Thompson submachine gun does not feature at all.

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Troops armed with M1 Garands and M3 Grease guns catch a ride on a Sherman tank in what might be the Bocage area of Normandy.

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A soldier with an M1 Garand helps up a BAR gunner during a street battle.

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A dramatic sequence begins with a tank mounted M1919A4 opening up.

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What appears to be an M2 Flamethrower in action.

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A charging German infantryman is dropped by a M1911A1. 

Lets take a look at some of the German weapons featured in the trailer, there are one or two interesting choices. The first German weapon we see is a P08 Luger. 

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A German soldier dismounts a burning tank, cocks and fires a P08 Luger as the voice over warns “the enemy is ruthless”. Interestingly, he appears to be wearing an infantryman’s uniform and equipment rather than typical tank crew uniform. 

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A vehicle mounted MG42 opens up during what appears to be a street battle.

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This is perhaps the most interesting weapon of the trailer. The screen capture shows the German infantryman who is shot and killed by an M1911A1 pistol. As he falls the profile of the rifle he has becomes visible. It appears to be a Soviet SVT-40 semi-automatic rifle.

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An SVT-40 (source)

This is an interesting rifle to include - the implications of its inclusion in a game, which the trailer appears suggest is predominantly set on the Western Front, are unknown. SVT-40 were captured from Soviet troops during Operation Barbarossa so it is conceivable this soldier managed to retain his SVT-40 when his unit was transferred west. 

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The heavy emphasis on the M3 submachine gun throughout the trailer is interesting as D-Day marked its first combat use. At the time the M3 had only recently begun to be issued to units. While I’m unsure of just how many were present during Operation Overlord, some were certainly issued to the US Airborne units, they were still being refined and did not become more widely issued until later in 1944. 

Aside from small arms the new trailer also features all manner of tanks, landing craft, and aircraft including a Tiger II. The Battle of Normandy was the first time the Tiger II saw action during fighting near Caen. This might suggest the battle for Caen will feature in the game. I’m looking forward to seeing what other weapons are going to be featured in the new game - let me know your thoughts, what do you make of the trailer? Call of Duty: WWII is due for release in November. 

Video Source


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Weekly Recap

This week we’ve covered everything from the M1 Carbine to the Italian Fiat-Revelli M1914. As well as an interesting Canadian lightweight Lee-Enfield and an early Owen Gun prototype chambered in .45 ACP. Check out the week’s posts below.

Thanks again for following, reading and supporting HF.  If you enjoy the content please consider supporting Historical Firearms through Patreon! As always if you have any questions, suggestions feel free to send me a message here.


Fiat-Revelli Modello 1914

.45 ACP Owen Gun Prototype

Experimental Long Branch Lightweight Rifle No.4

M1 Carbine

January HF Patreon Wallpaper - S&W Model 39

MG34

Quotes of the Day

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In Action: M1 Carbine

In the 1952 Pathe newsreel featured above shows M1 Carbines arriving in Malaya for issue to local police and white planters and miners. Pathe filmed the footage during the Malayan Emergency (1948-1960), when British and Malayan forces were engaged in counterinsurgency operations in response to the Malayan Communist Party’s, Chinese sponsored, guerilla war.

The film shows a group of white engineers, farmers and miners trading in their STEN MkII submachine guns for M1 Carbines. The narrator mistakenly called the M1 Carbines the “American MI type carbine”. These civilians were especially vulnerable to targeted attacks by Malayan Communist Guerillas. The authorities issued the weapons as personal defence weapons for their own protection against Guerrilla attacks. The men hand in their STEN guns (which appear to only have one magazine issued with them) in return for a carbine and a bandolier of .30 Carbine ammunition, held in stripper clips. Its interesting to note most of the white engineers also carry holstered revolvers and pistols.

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Malayan Police test the M1 (source)

Britain received over 200,000 M1 Carbines during the Second World War, as part of the Lend-Lease programme. After the war the British issued many of these to colonial paramilitary forces for use in counter-insurgency operations. The small, light M1 Carbine was originally intended for use as a personal defence weapon and was ideal for this use.

The film also shows armourers cleaning and function checking the carbines before issuing. A section of Malayan police are seen test firing their new carbines before the reel cuts to a mining engineer demonstrating the rifle to a group of young Malayan boys. The film ends with a shot of carbine rounds striking a rifle range silhouette target shaped like a Communist insurgent - complete with red star.

Sources:

Video Source
Image Source


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This afternoon [we] did a lot of shooting on the stern. The new carbine is a lovely little thing and very accurate.
-

Major General George S. Patton, then commanding the 2nd Armored Division, comments on the M1 Carbine in a letter to his wife Beatrice. Patton tested the rifle aboard the cruiser USS Augusta on 2nd November, 1942 on the way to the Operation Torch landings. 

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Patton aboard a motor launch with a M1 Carbine and M1 Thompson next to him (source)


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In Action: M1 Carbine

A glider pilot of the British Army’s Glider Pilot Regiment firing an M1 Carbine from the first floor front balcony of the Hartenstein Hotel in Oosterbeek. The Battle of Arnhem during the Operation Market Garden saw men of the Glider Pilot Regiment fight alongside the glider-borne 1st Airlanding Brigade and 4 Brigades of paratroops. Once landed the glider pilots fought alongside the men they had carried in their aircraft. They were armed with a range of weapons including Sten guns and Rifle No.4s. The M1 Carbine was issued in limited numbers to specialist troops, including glider pilots, by the British. 

Over 1,300 glider pilots landed in two waves during Market Garden, of these 229 were killed and 469 wounded or taken prisoner. 21 Glider Pilots fought at Arnhem Bridge with Colonel Frost’s 2nd Parachute Battalion.

Image Sources: 1 2 


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Prototype Suppressed M1 Carbine

Much of the history behind the suppressed M1 Carbine remains unclear. Developed by Britain’s Royal Small Arms Factory at Enfield for the OSS and SOE between 1943 and 1945. Based on standard receivers built by General Motors’ Inland Division, the carbines had a shortened 10 or 11 inch barrel, rather than the normal 18 inches. The weapon used a 13 or 17 inch long suppressor which screwed onto the receiver (the dimensions differ in various sources). The carbine weighed approximately 1.75 lbs more than the standard unsuppressed M1.

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An example of the suppressed M1 Carbine is held by the Springfield Armory (source)

The design had a ported barrel with seven 0.125 inch diameter holes enclosed by the suppressor which contained 10 metal back baffles surrounding the barrel. The suppressor had a small expansion chamber in front of the muzzle, followed by 11 cone baffles at the front of the suppressor housing. Unlike the standard carbine the suppressed M1 had to be manually cycled after each shot. In order to further mitigate the carbine’s report the weapon used a specialised subsonic .30 Carbine cartridge. As a result the suppressed M1 had to be manually cycled after each shot unlike the standard carbine.

The experimental section at RSAF Enfield built at least six examples although it remains unclear if any of the carbines ever saw action. A 1968 Frankford Arsenal report notes that the weapon sounded “like a sharp hand clap followed by a distinct hissing sound” with the weapon’s report peaking at 122 decibels. The report concludes that because “of its bulkiness, manual feeding, and not too impressive acoustical performance, it is doubtful if the weapon was widely utilized.”

Sources:

Silencers, Snipers & Assassins: An Overview of Whispering Death, D.J. Truby (1972)
Firearm Silencers, N. Wilson (1983)
Report R.1896, Silencers, Frankford Arsenal, L.W. Skochko & H.A Greveris (source)
U.S. Carbine M1 .30 SN# 474630, Springfield Armory, (source)
Image Three Source
Image Four source


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historicalfirearms:

John Garand’s .30 Calibre Carbine

In 1938 the US Army Infantry Board requested a new Light Rifle, this was initially opposed by the US Ordnance Department who did not wish to complicate supply and argued all troops could be armed with the new M1 Garand. However, June 1940 the Secretary of War overruled them and in October 1940, the Ordnance Department issued specifications for a new lightweight carbine. This required that the rifle be select fire, fire from a 50-round magazine and weigh no more than 5 lbs unloaded.

A large number of manufacturers including the government-owned Springfield Armory were called upon to submit designs. In May 1941, Springfield Armory submitted two designs one by Clarence Simpson and the other by John Garand. While Simpson’s design was not tested by the Army Garand’s was. Five of the prototype rifles were submitted for testing where it performed well against other designs during the Light Rifle Trials.

Garand’s carbine was simple with just 44 parts and could be stripped in 81 seconds. It weighed just under 5 lbs, Garand’s carbine was the only one to meet the weight requirement, and was fully automatic capable of rates of fire of between 700-900 rpm. In order to conform with the original specification the rifle could fire from 5, 10, 20 or 50 round magazines.

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The various Garand light rifle magazines, these capacities were requested by the Ordnance Department.

The layout of Garand’s carbine owes nothing to his earlier designs, instead it uses an unorthodox top mounted magazine which sits at a 45 degree angle to the receiver. Corresponding to this there was an ejection port beneath the receiver which later testing found threw spent cases on to the left arm of the operator (see image #4). The carbine’s charging handle sits horizontal at the side of the barrel and the weapon’s sights are offset to the left so the magazine housing does not obstruct the line of sight. Another feature was a combination rear sight and ejector piece which Garand patented in the late 1940s (see below).

The carbine impressed the Ordnance Department who liked its simplicity and found it functioned well in wet conditions. Garand’s gas system meant the carbine had good accuracy and low recoil. During the initial trials in May and June 1941, two Light Rifle’s impressed, Garand’s and one submitted by Bendix-Hyde.  

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Garand’s first ‘top-loading’ carbine patents (source)

However, the Ordnance Department’s report made some suggestions for the improvement of the carbine. They requested that the bolt be adapted to prevent accidental discharge as well as realigning the charging handle from the vertical to the right. It was also suggested that the stock be strengthened and standard sling swivels be used instead of the stock cut out. It was also requested by some of the evaluators that the magazine housing be moved to the more conventional position below the receiver. Although many of those who fired the rifle did not dislike the original magazine position.  

These changes along with the incorporation of a short-stroke tapped gas piston system like that found in Winchester’s design (developed by David Marshall Williams) were made in what was designated the Model D. In September 1941 the final major round of testing began. Five rifles were tested including Springfield’s Garand, the Bendix-Hyde, a new entry from Winchester (which went on to be adopted as the M1), a rifle from an inventor - Turner, and the entry from Reising.

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Ordnance Depart’s photographs of the Second Model Garand/Springfield Armory Light Rifle

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Garand’s Second carbine patent (source)

Each rifle was put through testing with 8,000 - 10,000 rounds fired for accuracy, endurance and reliability under simulated combat conditions. Garand’s ‘improved’ carbine was found to be less reliable and more difficult to disassemble. Springfield Armory’s attempts to improve the carbine also led to making it heavier at about 5.37 lbs. The carbine was tested for the final time in April 1942 however, by this time Winchester’s design had been adopted as the United States Carbine, Caliber .30, M1.

Souces:

Springfield Armory Museum entries: 1 2 3 4 5

The M1 Carbine, L. Thompson (2011)

The Army Gets a New Rifle, American Rifleman (September 1941), Maj. E.H. Harrison

Garand Carbine (source)

War Baby! The US Calibre .30 Carbine, L. Ruth (1992)

This post is part of a series of collaborations with Chuck Kramer of Gunlab who was kind enough to provide the photographs used in this article.


If you enjoy the content please consider supporting Historical Firearms through Patreon!

John Garand’s .30 Calibre Carbine

In 1938 the US Army Infantry Board requested a new Light Rifle, this was initially opposed by the US Ordnance Department who did not wish to complicate supply and argued all troops could be armed with the new M1 Garand. However, June 1940 the Secretary of War overruled them and in October 1940, the Ordnance Department issued specifications for a new lightweight carbine. This required that the rifle be select fire, fire from a 50-round magazine and weigh no more than 5 lbs unloaded.

A large number of manufacturers including the government-owned Springfield Armory were called upon to submit designs. In May 1941, Springfield Armory submitted two designs one by Clarence Simpson and the other by John Garand. While Simpson’s design was not tested by the Army Garand’s was. Five of the prototype rifles were submitted for testing where it performed well against other designs during the Light Rifle Trials.

Garand’s carbine was simple with just 44 parts and could be stripped in 81 seconds. It weighed just under 5 lbs, Garand’s carbine was the only one to meet the weight requirement, and was fully automatic capable of rates of fire of between 700-900 rpm. In order to conform with the original specification the rifle could fire from 5, 10, 20 or 50 round magazines.

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The various Garand light rifle magazines, these capacities were requested by the Ordnance Department.

The layout of Garand’s carbine owes nothing to his earlier designs, instead it uses an unorthodox top mounted magazine which sits at a 45 degree angle to the receiver. Corresponding to this there was an ejection port beneath the receiver which later testing found threw spent cases on to the left arm of the operator (see image #4). The carbine’s charging handle sits horizontal at the side of the barrel and the weapon’s sights are offset to the left so the magazine housing does not obstruct the line of sight. Another feature was a combination rear sight and ejector piece which Garand patented in the late 1940s (see below).

The carbine impressed the Ordnance Department who liked its simplicity and found it functioned well in wet conditions. Garand’s gas system meant the carbine had good accuracy and low recoil. During the initial trials in May and June 1941, two Light Rifle’s impressed, Garand’s and one submitted by Bendix-Hyde.  

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Garand’s first ‘top-loading’ carbine patents (source)

However, the Ordnance Department’s report made some suggestions for the improvement of the carbine. They requested that the bolt be adapted to prevent accidental discharge as well as realigning the charging handle from the vertical to the right. It was also suggested that the stock be strengthened and standard sling swivels be used instead of the stock cut out. It was also requested by some of the evaluators that the magazine housing be moved to the more conventional position below the receiver. Although many of those who fired the rifle did not dislike the original magazine position.  

These changes along with the incorporation of a short-stroke tapped gas piston system like that found in Winchester’s design (developed by David Marshall Williams) were made in what was designated the Model D. In September 1941 the final major round of testing began. Five rifles were tested including Springfield’s Garand, the Bendix-Hyde, a new entry from Winchester (which went on to be adopted as the M1), a rifle from an inventor - Turner, and the entry from Reising.

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Ordnance Depart’s photographs of the Second Model Garand/Springfield Armory Light Rifle

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Garand’s Second carbine patent (source)

Each rifle was put through testing with 8,000 - 10,000 rounds fired for accuracy, endurance and reliability under simulated combat conditions. Garand’s ‘improved’ carbine was found to be less reliable and more difficult to disassemble. Springfield Armory’s attempts to improve the carbine also led to making it heavier at about 5.37 lbs. The carbine was tested for the final time in April 1942 however, by this time Winchester’s design had been adopted as the United States Carbine, Caliber .30, M1.

Souces:

Springfield Armory Museum entries: 1 2 3 4 5

The M1 Carbine, L. Thompson (2011)

The Army Gets a New Rifle, American Rifleman (September 1941), Maj. E.H. Harrison

Garand Carbine (source)

War Baby! The US Calibre .30 Carbine, L. Ruth (1992)

This post is part of a series of collaborations with Chuck Kramer of Gunlab who was kind enough to provide the photographs used in this article.


If you enjoy the content please consider supporting Historical Firearms through Patreon!

About 30 percent of our carbines gave us trouble; some wouldn’t fire at all; others responded sluggishly. But the main reason my men lost confidence in the carbine was because they would put a bullet right in a Chink's chest at 25 yards range, and he wouldn't stop. This happened to me. The bullet struck home; the man simply winced and kept on coming. There were about half a dozen of my men made this same complaint; some of them swore they had fired three or four times, hit the man each time,and still not stopped him.
-

1st Lt Joseph R. Fisher, 1st Marine Regiment, gives his opinion on the M1 and M2 Carbines issued to US troops in Korea.

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M2 carbine in Korea (source)

Quote taken from:

‘Commentary on Infantry Operations and Weapons Usage in Korea, Winter of 1950-51′, Operations Research Office Technical Memorandum ORO-R-13, (Chevy Chase: Johns Hopkins University 19/06/1952), by Gen. S.L.A. Marshall

Recent Recap:

Once again my recaps haven’t been as frequent as I’d like, so apologies for that.  However, below are all of the recent posts about everything from the M1 Carbine to the ultra rate 1906 Luger Rifle.  There have been posts on some fascinating weapons like the Powell Device Luger and the M1901 Springfield experimental rifle.  

Over the last month of so there have also been a number of posts on armour, swords and the cleaning and conservation of metal arms and militaria.   Recent more miscellaneous posts and Historical Trivia posts have looked at everything from the death of gangster John Dillinger, the bombing of Hiroshima and the Warsaw Uprising to the Battle of Killiecrankie and the Canadian Autocar machine gun carrier. 

Last month also saw the introduction of two new features, the Historical Firearms Book Club which invited readers to submit reviews of their favourite history books.  This will hopefully be a monthly feature with the next in the series going up in mid September so start thinking about what you’d like to cover if you’re going to submit a review.

The other new feature is the Daily Definition series which looks at various military and firearms terminology and explains them with examples.  You can find a list of the terms covered already below.

Yesterday I posted a #WWI100 Recap, below are all the recent posts not related to the First World War.

Thanks again for following and reading, if you have any questions feel free to send me a message here.  Also don't forget to sign up for the Historical Firearms inbox service to receive daily or regular updates on content, find out more here.

__________________________________________________________

Firearms:

Powell Device Luger

Winchester Model 1900

Muzzle Blast: Ballistic Photography

M1 Carbine

1906 Luger Rifle

Brigadier General William Crozier, Chief of Ordnance - and all the weapons adopted under his tenure (BAR, M1903, M1911, Browning M1917, etc)

.30 Carbine Cartridge

Springfield Armoury Model 1901

Pattern 1914 & M1917 Enfield

Sword & Armour:

1796 Pattern Light Cavalry Sabre

1803 Pattern Light Infantry Sabre

Armour Cleaning

Historical Trivia:

Dillinger Killed

First Fixed Wing Aircraft shot down by a Helicopter

A British Luger

The White Ensign

Miscellaneous History:

Hiroshima

Canadian ‘Autocar’ Machine Gun Carrier

65 Years of the British National Health Service 

Battle of Killiecrankie

The Warsaw Uprising/Powstanie Warszawskie

Storming of the Bastille: 14th July, 1789

Daily Definitions:

Magazines, Clips and Chargers

ACP

Double Action

Stand To

Fog of War

Enfilade

Open City

The First Historical Firearms Book Club Post

.30 Carbine

In the late 1930s the US Army began lobbying for a new ‘light rifle’ or carbine to be issued to support troops for whom their personal weapon wasn’t their primary concern.   It was not until 1941 that Ordnance Department’s the Light Rifle Trials began seeking a new carbine.  However, by that time the rifle’s cartridge had been chosen.

The light rifle was intended to bridge the gap between the .30-06 chambered M1 Garand battle rifle and the M1911 pistol in .45ACP - which was frequently issued to support troops as their main defensive sidearm.  The new rifle would need a cartridge which was accurate and hard hitting but not as large as the .30-06 round.  
The .30 Carbine round had its origins in a much older Winchester cartridge the .32 Winchester Self-Loading round which had initially be developed for the Winchester Model 1905 self loading rifle. 

The .32 Winchester Self Loading (.32WSL) has a slightly heavier bullet weighing 165 grains to the .30 Carbine’s 110gr.  The .32WSL has a shorter case as a result the Carbine round had a higher muzzle velocity leaving the barrel at 1,900 feet per second.  This increased velocity was also the result of increased power from newer chemical propellants than its parent cartridge.  The case itself is straight and rimless, unlike other contemporary rifle ammunition it is neither necked nor is the projectile pointed like a conventional spitzer bullet.  The new ammunition went into production in February 1941, as the Ball Cartridge Carbine Caliber .30 SL, M1.

The .30 Carbine’s parent cartridge the .32 Winchester Self-Loading Cartridge (source)

The light rifle selected was a design from Winchester, adopted in October 1941, as the M1 Carbine.  It chambered the new round making it a light, handy rifle with light recoil which meant it was easy to shoot and ideal for troops who were specialists and did not have the time for full marksmanship training.  It proved to be an excellent intermediate between the M1 Garand and the M1911, so much so that it was increasingly issued to squad leaders and officers. However, it was noted by troops fighting in the Pacific Theatre that the round did not penetrate dense jungle well. Similarly, later during the Korean War there were numerous after-action reports noting the lack of stoping power of the .30 Carbine round even at close quarters. This was due to its ball projectile and lower velocity than a full-sized .30 calibre round.

While the .30 Carbine cartridge could be described as an intermediate round, it is not in the same category as the German 7.92mm Kurz - a true intermediate calibre which maximised power and accuracy while minimising size and weight.  

Source:

Image One Source

Image Two & Three from Popular Science, June 1942 (source)

The Greenhill Military Small Arms Data Book, I.V. Hogg, (1999)

Military Small Arms of the 2oth Century, I.V. Hogg & J. Weeks, (1985)