夜間戦闘機
Jabs had a second armament modification made a few months later. Night fighter pilots had been asked to identify their targets before firing upon them to reduce friendly fire accidents. To their surprise, the night fighter pilots discovered they could fly below a heavy British bomber and remain out of sight and undetected. Soon pilots were asking for upward firing guns to be mounted in their aircraft. These modifications were largely done in the field. Jabs had a pair of upward firing 20 mm cannons mounted to his Bf 110. If he could locate the bomber he would approach from below, matching the weaving movement of the bomber. With the target confirmed Jabs would fire from below, aiming for the fuel cells in the right wing root between the fuselage and the inboard engine. This gun mounting they called "Schräge Musik" or slanting music. The bombers shot down in this manner never saw their attacker. Its use remained unknown to Bomber Command for over a year. It was soon the preferred method of attack. Jabs scored 7 kills in June, bringing his total to 35. By the end of August he had reached 40. On 31 August 1943, he was awarded the German Cross in Gold ().