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Special Article: Intermediate Caliber Repudiation?[/SIZE]
Article from
Le Spectateur militaire.
On February 12th, the German Heereswaffenamt
Ballistische und Munitionsabteilung (the Ballistical and Ammunition Branch of the German Army Armaments Office) confirmed reports that they would procure the Swiss SK-42 rifle, known to the German Army as the G5, for standard use by all branches of the Heer. This monumental decision is highly noteworthy, as the G5 rifle is chambered for the 7.92x57mm Mauser rifle round, not the 7x40mm round adopted in 1931. The German newspaper
Frankfurter Zeitung, in an article published February 16th, reported that the Waffenamt's decision was based on the poor performance of the 7x40mm Kar.37 semiautomatic rifle, which suffered continued stoppages (failures to feed or extract the cartridge) as well as high corrosion in the barrel. The German Ministry of Defense declined to comment on the matter. While this appears to have satiated the opinion of the laymen,
Le Spectateur militaire's staff believes the real reason for the Waffenamt's decision is not as simple as Frankfurter Zeitung reports.
By procuring the G5 rifle for all branches of the German Army, the Waffenamt's decision will terminate all production of the Kar.31 and Kar.37 rifles, the only German weapons chambered for the 7x40mm round. While production of the 7x40mm round will undoubtedly continue in order to maintain stockpiles for existing weapons, it appears that the Heer has decided to abandon further development and production of 7x40mm chambered small arms in favor of the 7.92x57.
The First Intermediate Cartridge
Development of the 7x40mm cartridge appears to have started in the late 1920s. German cartridge designers claim the round - and a number of other rounds considered for adoption - was spawned by the Gewehr-Prüfungskommission's studies of combat ranges on the Eastern Front of the Great War. As discussed in the May 1941 issue of
Le Spectateur militaire, these "intermediate cartridges" ostensibly provide the shooter with less recoil, which translates into faster follow-up shots, at the expense of range, accuracy, and hitting power.
Although details are not entirely clear owing to the Heereswaffenamt's silence regarding their internal politics, it appears that the German intermediate cartridge advocates, led by the then-head of the Heereswaffenamt, Oberstleutnant Karl Becker, found themselves superbly well-placed within the Heereswaffenamt during the period between 1930 and 1936 to adopt a cartridge of their choosing, regardless of the consequences to the German Army. In May 1929, the Heereswaffenamt placed a request for proposals for a self-loading rifle chambered in an intermediate cartridge, with a case length not to exceed 45mm. Specific instructions were given to ensure that the trajectory and accuracy of the new round would be comparable to the 8x57mm Mauser out to a range of six hundred meters.
A number of prominent German generals have stated that the original intermediate cartridge was proposed primarily to lower the size and weight of bolt-action carbines used to arm support troops (for instance, artillerists, mortar operators, tank drivers, and vehicle maintenance personnel). It did not became clear to many senior German Army commanders that Oberstleutnant Becker and his fellows within the Heereswaffenamt intended to change the caliber of all frontline small arms until late 1931, by which point the 7x40mm round had already been selected, and significant quantities of Kar.31 rifles were ordered for the Heer. Becker initially reassured opponents that the Kar.31 would be limited to support troops only, and appears to have kept this promise until 1933, when the first frontline infantry troops began receiving Kar.31s. Becker then used bureaucratic inertia as an argument against returning to the 8x57mm round.
When the German Army, traditionally one of the world leaders of small arms innovation, adopted the 7x40mm round in 1931, world small-arms developer took note. The Indian Army, which aped most German developments of all types since the 1900s, quickly adopted their own 7x40mm round, although it now appears to be in more limited service than Western army observers once thought. Other countries, most notably Great Britain, began development of similar intermediate cartridges.
Controversy
In 1931, while prominent members of the Waffenamt strongly pushed for the development of the 7x40mm cartridge, a number of voices were raised in opposition to the round's adoption. The most prominent of these came from the Gebirgsjäger (Mountain Infantry) troops, who felt the 7x40mm round lacked the range and punch necessary for their anticipated tactical employment. According to documents released by Gebirgsjäger commanders, the expected engagement ranges for rifle combat, as proven from Great War experience, usually exceed three hundred meters, sometimes ranging up to five hundred meters. Although the 7x40mm round's advocates in the Waffenamt insisted that the 7x40mm round is "flat-shooting" and has sufficient range for these sorts of engagements, it shall be shown later that this is not the case.
Further objections, not as loud but carrying perhaps more weight, came from within the German Army's quartermaster corps, which objected to the principle of supplying more types of ammunition. According to the German Army's tables of organization and equipment, each squad would still receive quantities of 8x57mm Mauser ammunition for the squad's MG33 or MG3 general-purpose machine gun, while infantrymen would receive 9mm Parabellum and 7x40mm ammunition for their sidearms, pistols, and rifles. The quartermaster service believed it would be better, if possible, to use a single cartridge for both the infantryman's rifles and the squad machine gun. Some proposals to create a 7x40mm-chambered squad machine gun were advanced, but went nowhere following a series of angry exchanges within the Waffenamt itself. All experts on machine-gun design adamantly insisted that the 8x57mm Mauser round be retained in German squad machine guns.
All of these objections, however, are minor compared to the main issue of the round's suitability. The intermediate round's advocates in the Heereswaffenamt claimed that the 7x40mm round performs on par with the 8x57mm round out to four hundred meters. This is not, in fact, the case.
An Unsuitable Cartridge
The 7x40mm round was billed as an ideal cartridge for modern military service, permitting lighter recoil for faster follow-up shooting by automatic and semiautomatic rifles. It appears that this has been achieved at the expense of other qualities desirable in military ammunition.
In 1935, as part of a trial for new small arms, the French Army tested three German Kar.31 rifles chambered for the 7x40mm cartridge. The results, given in a report declassified in 1942, show how the 7x40mm round performs badly at range compared to the standard 8x57mm round. These tests, conducted in a variety of climates, reportedly caused significant backlash among the Armee de Terre's own weapons designers and evaluators, who rejected the intermediate rifle rounds proposed at that time.
[SIZE=1]A comparison of bullet drop between the 7x40mm round and 8x57mm round.[/SIZE]
Despite these results, 7x40mm proponents within the Waffenamt still proclaimed that their intermediate round was "flat-shooting", a claim which seems incredible when viewed objectively.
The French Army's 1935 tests also evaluated that bullet drift due to wind, air pressure, and temperature variations caused similar inaccuracy in the horizontal plane. One French soldier responsible for testing the German Kar.31s reportedly said "Beyond three hundred meters, the Kar.31 is only marginally more effective than spitting at the enemy."
Proponents of 7x40mm cartridge claim that these results are part of the attraction of the intermediate rifle round - a feature of the design, rather than a failure of it. According to the Gewehr-Prüfungskommission studies cited by the Heereswaffenamt in 1929 (which have unfortunately never been released to the public), combat ranges on the Eastern Front and Balkan Front during the Great War dominantly took place between the ranges of fifty to a hundred and fifty meters. This is well within the 7x40mm cartridge's range of best accuracy. With lighter recoil and smaller size, the soldier can take faster follow-up shots, and carry more ammunition.
These arguments may carry weight. However, empirical data from a number of recent military engagements appears to fly in the face of the cited Great War studies. According to figures released by the Chilean Army in the aftermath of the Andean War, Chilean infantry generally engaged the Bolivians at three hundred to five hundred meters. These results were confirmed by the Irish, Czechoslovakian, and Yugoslavian Armies during their participation in the Afghanistan Peacemaking Operation, as well as by French forces in Morocco. Similar studies of Persian Civil War battle reports echo this trend, although less data is available. Combat ranges in the South American War differed drastically based on the region of the fighting, so examples of both point-blank and long-range rifle combat may be found. Indeed, the only recent example that appears to confirm the opinions of lower combat ranges comes from the Wilno Rebellion in Lithuania. In this case, however, ranges were generally low enough that submachine guns chambered in pistol calibers, rather than rifle fire using intermediate rounds, seems to have been more useful.
The Armee de Terre's tests also investigated the 7mm bullet's ability to wound and kill. Firing at slabs of beef or blocks of gelatin, the inspectors determined the 7x40mm bullet had a marked tendency to leave a very narrow, straight wound channel. Postulating its effect on a human, this means that a gunshot wound would be less serious than it could otherwise be. The 7x40mm bullet design appears to underperform in this fashion even compared to similar 7mm rounds such as the American .276 Pedersen (7x51mm) and the smaller 6.5x51 FAR, both of which demonstrate tendencies to yaw when striking flesh, increasing the potency of the bullet. In fact, in terms of wound channel width and depth, the 7x40mm rifle round shows almost no advantage over the 9x19mm Parabellum round fired from a submachine gun!
While the aimed rate of fire for a 7x40mm-chambered semiautomatic rifle rises somewhat in comparison to the 8x57mm-chambered alternative, it is important to realize that the majority of the German Army's intermediate-chambered rifles are actually bolt-action Kar.31s rather than semiautomatic Kar.37s. The Kar.31's rate of fire thus depends entirely upon the rifleman's skill at working the bolt, chambering a new round, and re-acquiring his target; the low recoil of the 7x40mm round has almost no role to play in this process. When chambered in semiautomatic rifles, the 7x40mm round does provide a substantial increase in both aimed and unaimed rate of fire. However, semiautomatic rifles still have a rate of fire significantly below both 9mm-chambered submachine guns and the Heer's highly potent squad machine guns.
By comparison to the Armee de Terre's cartridge tests in 1935, the Heereswaffenampt's 1931 trials were unusually abbreviated, and aimed at choosing from one of the five intermediate cartridges rather than comparing their suitability against the 8x57mm Mauser. Accuracy and ballistic tests were only conducted out to two hundred meters in low wind conditions and in moderate temperatures, where the intermediate rifle rounds were most closely comparable to the 8x57mm. A rifle chambered for the American .276 Pedersen was also presented for evaluation, although Lt. Colonel Becker rejected it out of hand as the case length was longer than the specifications required. The winning entry amongst the five intermediate cartridges was the 7x40.
In a February 1942 demonstration, Gebirgsjäger Regiment 4 conducted a series of small arms exhibitions to demonstrate the capabilities of the Swiss-designed G5 rifle, chambered in 8x57mm Mauser. As part of the demonstration, troops shot at automated moving targets at a variety of ranges up to five hundred meters using the bolt-action 7x40mm Kar.31, the semiautomatic Kar.37, the MP-36 submachine gun, and the 8x57mm-chambered semiautomatic G5. At ranges under one hundred and fifty meters, the MP-36 submachine gun achieved the most hits (albeit with a 170% larger expenditure of ammunition per hit), while the Kar.37 and G5, with aimed fire from both standing and prone positions, achieved roughly identical but lower numbers of hits. Beyond one hundred and fifty meters, the MP-36 submachine guns failed to achieve almost any hits. The Kar.31 and Kar.37 rifles also showed significant drops in accuracy out to three hundred meters, at which range they ceased to be an effective factor in the competition. Only the 8x57mm-chambered G5 was successful at hitting targets reliably throughout the entire engagement range. An observer for the German
Militär-Wochenblatt summed up the results in a comment to the regiment's commander: "The 7x40mm-chambered rifles appear to have no place in the front line troops."
Rejection
A year after Gebirgsjäger Regiment 4's demonstration, the Heereswaffenamt, now under new leadership since Becker's retirement, indicated that all combat branches of the German Army would be equipped with the 8x57mm-chambered G5 rifle. Although it will take some time for production to catch up to the Heereswaffenamt's decisions, this announcement appears to spell the doom of the 7x40mm cartridge.
It remains to be seen what the German decision to move away from the intermediate rifle cartridge will have on other foreign developments. The Indian Army, the only other user of the German-designed intermediate cartridge, has not put as many 7x40mm-chambered firearms into service as intelligence sources have previously thought. It has only recently come out that the Imperial Ordinance Board is developing and testing alternate weapons and calibers. The political criticism once aimed at the IOB for their conservatism in adopting the 7x40mm has decreased substantially in recent years, and the government has made no official comments on the issue of small arms.
The British, by contrast, still seem interested in developing their own .280 (7x43mm) intermediate rifle round. No firearms chambered for .280 have yet been demonstrated in declassified circumstances, and so the British round's comparability to the German 7x40mm remains a matter of conjecture.
The United States, France, Atlantis, and Russia have all adopted calibers that are much larger than the intermediate rounds proposed by Germany and Britain. In 1936, France, Atlantis, and Russia introduced the Type-36 semiautomatic rifle and the Type-37 general machine gun, both in the 6.5x51mm FAR cartridge. The FAR armies are reportedly extremely pleased with their choice of calibers, although both France and Atlantis have continued to experiment with small-arms calibers. It seems probable at this point that these developments are purely for experimental data, rather than serious consideration for a new rifle round.
By contrast, the US Army has adopted the .276 Petersen (7x51mm) rifle round which was rejected in 1931 by the Germans. Like the Germans, the US Army has not yet switched over their machine guns to the .276 caliber, partly due to difficulties caused by the extreme taper of the Petersen round. However, the US Army also began low-rate production of the M1 Carbine chambered for the .276 Petersen Carbine, a 7x36mm round that's smaller than the German 7x40. This has seen more widespread service, being sold to Chile, Ireland, and according to rumors, the Philippines. In all cases, the M1 Carbine seems to be tailored not towards frontline troops, but to rear-echelon soldiers (artillerists, supply troops, who place greater value in lightweight weapons rather than long-range engagements. In these circumstances, the M1 Carbine appears to take on the role of a cheap long-ranged submachine gun.
Given the American experience with the M1 Carbine, one has to wonder what the German experience with the 7x40mm round might have been had it only been distributed to the rear-echelon troops, rather than foisted off on frontline soldiers.
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Friday, April 26th 2024, 6:56pm
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