In June 1917 the German Army got a rude awakening with the first Allied Mark IV tanks. The German standard 7.92mm round had no effect on the new tank weapon armor, so while the German Army tried to develop their own tanks, Mauser began to design the first anti-tank rifle by using an up-scaled round of 13.2x92mm with a steel core. It took until May 1918 to get the guns operational but they were mass produced and over 15,000 were produced by the time the war ended. The rifle was huge, with a bipod fitted and a pistol grip. The barrel was 40" long and the recoil could break a soldier's collar bone, arm, or dislocate a shoulder as there was no muzzle brake nor buffer pad. It was serviced by a crew of two- an ammo feeder and a firer. The massive gun was effective in pentrating Allied armor but German tanks were needed and only 20 A7Vs got to the battlefield. Most broke down. Mauser continued with the design for a MG-18 TuF (Tank und Flieger) using the same round for AT and aircraft use. What is amazing is the crews of these weapons that had German body armor fitted in WW1 as range of the weapon was between 100-500m! Quite a sight in WW1. During WW2 the Germans had 3 main types of AT guns firing tungsten penetrators, the most effective being the imported Swiss 20 mm Solothurn S-18/100 pictured below!!!

http://oelund.skumleren.net/post-535-1184014369.jpg http://img177.imageshack.us/img177/7481/97429785ex9.jpg Solothurn S-18/100: http://rpmedia.ask.com/ts?u=/wikipedia/commons/thumb/5/5c/Bundesarchiv_Bild_101I-189-1250-10%2C_Russland-S%C3%BCd%2C_Soldat_mit_Panzerb%C3%BCchse.jpg/300px-Bundesarchiv_Bild_101I-189-1250-10%2C_Russland-S%C3%BCd%2C_Soldat_mit_Panzerb%C3%BCchse.jpg