The Messerschmitt Me 410 Hornisse (Hornet) was a German heavy fighter and Schnellbomber used by the Luftwaffe during World War II. Though an incremental improvement of the Me 210, it had a new wing plan, longer fuselage and engines of greater power. The changes were significant enough for the aircraft to be renamed the Me 410. The major change between the Me 210 and 410 was the introduction of the larger (at 44.5 litre, 2,715 in3 displacement) and more powerful Daimler-Benz DB 603A engines, which increased power to 1,750 PS (1,730 hp, 1,290 kW) compared to the 1,475 PS DB 605s used on the Me 210C - the interim Me 310 design experiment actually used the DB 603 powerplant choice first. The engine performance increased the Me 410's maximum speed to 625 km/h (388 mph), greatly improved rate of climb, service ceiling, and most notably the cruising speed which jumped to 579 km/h (360 mph). U4 which used the 50 mm (2 in) Bordkanone series weapon, the BK-5 cannon with 22 rounds (21 rounds to load and 1 extra round already loaded into the cannon), to turn either an Me 410A or B-series aircraft into a dedicated bomber destroyer. The BK 5 cannon - derived from the Panzer III tank's main armament, the 50 mm (2 in) KwK 39 L/60 - allowed the Me 410s to shoot at their targets from over 914 m (1,000 yd), a distance at which the bombers' defensive armament.