Messerschmitt Bf.110F

The Messerschmitt Bf.110F a development of the previous Bf.110E version, with a strengthened airframe and better armour. It was powered by two inverted-V 12-cylinder Daimler-Benz DB601F engine whcih yielded a power of 1332hp and drove a three-bladed propeller.
It was armed with two forward-firing 20mm MG/FF placed in the nose with 120 rounds, another four foward-firing 7.92mm MG.17 with 1200 rounds each and one flexible rearward firing 7.92mm MG.15 with 750 rounds.
Some sub-variants of it were made, most of them being field modifications and not factory made. The Bf.110 F-1 was the fighter-bomber sub-variant, the Bf.110 F-2 was a dedicated long-range zerstörer version equipped with extra underwing fuel tanks, the Bf.110F-3 was a long-range reconnaissance version with cameras and the Bf.110 F-4 was a night-fighter version fitted with a radar and a third crew-member to operate it. A field modification was made, the Bf.110 F-4/U1 which featured the Schräge-musik gun system. Usually it was two 20mm MG/FF cannons placed at the rear of the cockpit, with the muzzles protruding above the canopy glazing in order to shot the bombers from below in an oblique-oriented manner.
It wasn't the most produced variant, as only 169 exemplars were made. Four by Gothaer Waggonfabrik (Gotha) and 165 by Luther-Werke a small manufacturing company owned by MIAG. All of them were manufactured during 1942 and 1943.
It was in the night fighter role that the Bf.110 achieved its greatest success specially when armed with the Schräge-musik system which turned to be surprisingly effective. Heinz-Wolfgang Schnaufer, one of Luftwaffe's night fighter aces, and the highest scorer during the defence of the reich campaign, scored 121 kills, all of them achieved with different variants of the Bf.110. Some others, like Helmut Lent, switched to the night fighter section and improved their modest score as daylight pilots. There were some other aircraft that took part in the aerial night defence of Germany, like the Dornier Do.217, which was essentially a night-fighter conversion of the Dornier Do.17, or the Junkers Ju.88 on its C, R, and G variants, but none of them achieved greater success than the Bf.110.

Sources:
1. https://en.wikipedia.org/wiki/Messerschmitt_Bf_110
2. https://en.wikipedia.org/wiki/Messerschmitt_Bf_110_operational_history
3. https://forum.valka.cz/topic/view/76812
4. Salamander Books- The Complete Book of Fighters