The K5 railway gun “Leopold” was a 28cm (283mm) heavy howitzer in service with the Wehrmacht between 1937 and 1945. It was developed and built by Krupp, with a total of 27 guns. They saw combat action in France, emplaced near the coast of the English Channel. In 1944, a German artillery unit was equipped with K5 guns, pounding heavily on Allied positions at Anzio, about 45 miles to the south of Rome, during the Allied invasion of Italy. In the early months, 1944, this monster artillery piece played a heavy role at battering the Allies at the Anzio beachhead. The K5 had also been used by the German 22nd divisional artillery group in June, 1942, during the Siege of Sevastopol in Crimea; it had been fielded alongside Schwerer Gustav , Thor, and Gamma heavy guns to destroy the Russian concrete fortresses and bunkers.
The K5 gun fired 255-kg shells out to a range of 50 miles (70 km). This railway-mounted howitzer was officially designated K5 Tiefzug 7-mm, because its 22-m-long barrel was fitted with twelve 7-mm-deep grooves, which were deeply incised rifling. It had a rate of fire of 15 rounds per hour and a muzzle velocity of 1.12 m/s. Its elevation ranged from +10º to +50º, with a 2º traverse. The whole artillery piece was mounted on one pair of 12-wheel boggies. Total weight: 218 tons.