December 30, 2019
The stalemate of the trenches on the Western Front during World War I led directly to the development of the tank. Both the British and the French came to the same conclusion, the need for armored vehicles to enable their troops to cross no-man’s land. While their tank designs differed, both countries developed models capable of breaking through the German lines. The emergence of these armored behemoths on the battlefield required a response by the German military. One counter-measure was the 13.2mm Tank und Flieger (Tank and Aircraft or TuF) cartridge seen here. This big 13.2x92mmSR cartridge was designed for one purpose, to punch holes in the relatively thin armor of the early British and French tanks, and next generation aircraft, appearing on the battlefield.
What the German Army needed in 1917 was a cartridge which provided increased range and penetration over the existing 7.92x57mm Spitzgeschoss mit Kern or K-type AP ammunition. This featured a tool-steel core to aid penetration. As British tanks evolved their armor was becoming thicker and more difficult to defeat. While the original British Mk I tanks had armor 8mm thick, the improved Mk IV was protected with 12mm thick armor plate and the later Mk V’s frontal armor was 16mm thick. The French Saint-Charmond featured armor between 11mm (sloped) and 17mm thick on the early models while the small Renault FT-17 was up to 22mm thick. The 7.92x57mm K bullet only had a 33% chance of penetrating 12-13mm of armor at 100 meters. So, the German infantry needed the capability of penetrating not only existing but future threats as well. Ideally the cartridge would possess sufficient velocity and penetration to allow engagement of enemy armor at 400+ meters. These early British and French armored vehicles were very slow, moving not much faster than a walking man, so they made ideal targets for a cool-headed and steadfast gunner.
The German Army also needed a moral booster for their front-line troops. While these early British and French tanks had a myriad of problems, they were terrifying to the troops facing them. Nothing like them had previously been used on the battlefield and many German troops fled at their first appearance. The German High Command needed an effective weapon system capable of tackling tanks which would instill confidence back into their troops. While forward placed field guns proved their worth as tank-killers, the infantry needed to be able to destroy enemy tanks on their own. What they needed was an easily portable tank-killer the average infantryman could effectively employ.
To meet this need development work began on an anti-tank rifle and suitably powerful cartridge for it in 1917. In response to the need Polte Ammunition Factory designed an entirely new 13.2x92mm Semi-Rimmed cartridge. This large round drove a .535-caliber 795-grain Armor Piercing bullet at approximately 2,575 fps. In doing so it generated a whopping 11,703 ft-lbs of energy. The cartridge saw combat chambered in an equally large single-shot bolt action anti-tank rifle, the Mauser Tankgewehr M1918. The combination provided the Kaiser‘s tank-killer teams with an easily portable weapon capable of penetrating 26mm (1 inch) of armor at 100 meters. This was a dramatic improvement over the 7.92x57mm K bullet. The 13.2mmSR TuF could penetrate 23.5mm of armor at 200 meters, 21.5mm at 400 meters and 18mm (.71 inch) at 500 meters. This was sufficient for tackling the ponderous, slow-moving and lightly armored British and French tanks of the day which creeped through the mud at a snail’s pace.
The Tankgewehr M1918 rifle was developed by Mauser and was basically built on an enlarged Mauser action with features of the Gew 88 and Gew 98. It had three gas relief ports at the front of the bolt, as well as a reinforced cup area at the back of the bolt to vent gas away from the rifleman. Rather than the dual-opposed locking lugs the bolt featured four lugs, two at the front and two more at the rear. A single-shot design, each round had to be manually loaded into the chamber which slowed the rate of fire. It was conventional in layout, just very large. Overall length was 5 feet 7 inches and it weighed in at 35 pounds. Weight grew to 41 pounds when loaded and fitted with the MG 08/15 type bipod.
While it featured a pistolgrip to make it a bit easier to handle, there was no method for reducing recoil. It lacked both a muzzle brake and recoil pad, so firing it was a jarring experience. Keep in mind, the average German infantryman of this time period stood only 5 feet 6 inches high and weighed about 130 pounds. Regarding recoil, gunners complained of temporary deafness, headaches, stiff neck and bruising/dislocated shoulders. Conventional iron sights were fitted delineated to 500 meters. Approximately 16,000 to 28,000 (numbers vary) Tankgewehr M1918 rifles were produced at cost of ℳ1,000 Marks each.
It was intended to be served by a 2-man crew, gunner and loader/spotter. They were issued about 132 rounds of 13.2mmSR AP ammunition in three 20-round leather bags and a 72-round box. The two of them would act as a tank-killer team, quickly moving the gun into position and aiming for maximum effect per cartridge. They would try to target the tank drivers, machine gunners and engine/fuel tanks. Killing the driver/machine gunners would allow grenade parties to manuever on the vehicle and destroy it. While the 13.2mmSR TuF cartridge provided the required penetration, the guns low rate of fire reduced its combat effectiveness. The gunner needed to have experience and calm nerves to disable a tank with a single-shot bolt-action rifle.
It was also planned to chamber the 13.2mmSR TuF in a watercooled machine gun. The design was basically an enlarged MG 08/15 water-cooled machine gun called the M1918 TuF. The German firm of MAN basically scaled the MG 08/15 up sufficiently to handle the much larger cartridge. Operation was via Maxim’s short recoil, locked breach with a toggle lock. It fired from the closed bolt position. Rate of fire was 500 rpm and feed was from traditional cloth belts. To prevent over-heating it was fitted with a conventional water jacket for cooling. The gun itself weighed approximately 81.4 pounds. A special pedestal mount was designed for anti-aircraft use while a large wheeled carriage, weighing 189 pounds, was developed for ground use.
A contract for 4,000 13.2mmSR M1918 TuF machine guns was placed with MAN early in 1918 by the German Army. Due to the chaos towards the end of the war only approximately 50 guns were produced before the surrender. It is not believed any of these 13.2mmSR M1918 TuF machine guns were actually fielded in combat. If they had been their combat performance on the slow moving and lightly armored tanks of the day would have been impressive. They would have been able to engage enemy armor at 500 yards firing 795-grain AP ammunition at their 500 rpm cyclic rate. Unlike the bolt-action single-shot Mauser Tankgewehr M1918 rifle, the 1918 TuF machine gun would have been able to rake a tank with an extended burst of 13.2mmSR AP shells before moving on to the next target. Had they been available in quantity in 1917 the 13.2mmSR 1918 TuF machine gun could have had a large impact on the combat performance of British and French armor. But it was not, and most of the examples which were produced were destroyed by the Allies at the end of the war. Only a few museum pieces remain today.
While the 13.2mmSR TuF cartridge’s life was relatively short, it had a profound impact on an entire generation of cartridges which came after it. Even our .50 caliber Browning Machine Gun cartridge felt its influence. Today the 13.2mmSR TuF cartridge is an interesting and quite collectible piece of military history.