Armament was to center on a large caliber 128mm Kw.K 44 L/55 main gun. The barrel was smooth and relatively featureless, showcasing no noticeable muzzle brake of any kind. The main gun had the power to penetrate the armor of any Allied tank being fielded (including the Soviet JS-2 and T-34/85, British Churchill or the American M4 Sherman) at any angle and at ranges of 3,500 meters or more. A rangefinder was proposed for the design, this to be produced by Zeiss, though the system was never fully completed. Per Hitler's orders, there was the 75mm Kw.K 44 L/36.5mm gun co-axially fitted to the turret, sitting and operating alongside the large caliber main gun. This two-gun arrangement would no doubt had given the Maus a mobile battlefield punch yet unseen in all of the war. Secondary armament included just a single 7.92mm MG34 general purpose machine gun for anti-infantry defense as well as any personal weapons carried by the crew. Ammunition for the 128mm main gun would have been approximately 55 to 68 projectiles of varying explosive/penetration types. Likewise, there would have been variety in the 200 projectiles for the 75mm gun as well.
The Maus V1 Prototype
The first prototype - VI - became available on December 24th, 1943 at the Alkett plant. The tank was completed without the production turret and fitted with a Daimler-Benz MB 509 12-cylinder engine of 1,080 horsepower - a highly modified form of the Daimler-Benz DB 603 series aircraft engine. For the interim, the V1 was fitted with a dummy turret that promoted the weight and size of the soon-to-be production model. She was painted over in a forest camouflage paint scheme and awarded Soviet tank markings to mimic a captured Russian vehicle, this so as to not arouse any suspicion about the ongoing supertank project. In general testing, the immense weight of the tank soon became apparent and movement was highly restrictive. Additionally, the suspension system lacked the overall capability to balance the weight of the heavy tank. As if the those issues were not enough, it was realized that no bridge in Europe could realistically allow passage of such a creation. To remedy the latter issue, developers installed a snorkel system that would allow the tank to traverse up to 26 feet of water. To remedy transportation over longer distances, a specialized railway car was devised for such duties. Graz-Simmering-Pauker Works of Vienna produced the 14-axle train car.
Krupp eventually designed the production turret but this was never installed on the V1, which made due with the "simulated" turret for the rest of its tenure.
The Maus V2 Prototype
The second prototype - V2 - appeared in March of 1944. Again the tank initially existed without the production turret, which had yet to be completed at the Krupp factories. Additionally, the powerplant did not arrive for fitting until later in 1944. Krupp eventually delivered the turret component on April 9th, 1944, and the system was promptly fitted onto the V2 chassis for testing. The engine, this time a Daimler-Benz MB 517 series diesel system of 1,200 horsepower - finally arrived in September of 1944 and was installed in the V2. Despite the new powerplant and a new electrically-powered steering system, the new arrangement offered little in the way of performance gains. Testing for the V2 began in September of 1944.
The End of the Maus
In July of 1944, Krupp had completed two more hulls and reported that two more would soon become available. However, a few days later, Krupp was ordered to cancel further production of these four hulls altogether. In fact, the completed hulls were ordered to be scrapped with all work stopping by August of 1944.
At the end of the war, the V1 pilot vehicle fell into Soviet hands, the Red Army being the first to reach her. The hull was then mated to the completed turret of the captured V2 prototype (itself destroyed by the Germans) for testing and arrived in the Soviet Union on May 4th, 1946. Though general evaluation of the system occurred in the years following the war, it is commonly accepted that the Maus did not influence Soviet tank design in any way. Tests were conducted at Kubinka from 1951 to 1952 to which the Maus was then offered up as a trophy piece for the Museum of Armored Forces (Kubinka Tank Museum) in Kubinka, Russia.
The V2 was last seen being sent to the defense of Berlin but the machine broke down somewhere near Zossen. She was subsequently destroyed by her crew to prevent her capture by the enemy and never fired a shot in anger. As mentioned above, her turret was refitted into the V1 hull by the Soviet Army using six 18-ton half-tracks - for it alone weighed some 55 tons.
A third incomplete hull was found at the Krupp factory in Essen.
The Krupp P.1000 Ratte
Despite its size, the Maus would have been dwarfed by the incredibly large Krupp P.1000 "Ratte" 1,000 tonne tank detailed elsewhere on this site. This system - with construction started but never completed by war's end - would have fielded 2 x 280mm main guns in a navy-type turret, 1 x 128mm gun, 8 x 20mm Flak 38 series anti-aircraft guns and 2 x 15mm Mauser MG 151/15 guns making it easily the largest and more powerful tank ever built.