Pavel M

AIMS G-4 set has both Mk108 and MG151 in it… Mk108 is for nose for Bf-110G-4/R3 and MG151 is for belly. On your picture is Mk108, MG151 body looks like this:

Mk108 in the G-4 conversion is for R3 mod - twin Mk108 up in the nose. This was widely used by G-4 night fighters but very rare for day fighters. Mk108 had low muzzle velocity (it was more like automatic granade launcher than canon) and required to get to close range to the target which was very dangerous for slow Bf-110 in day time. For the Bf-110G only option for belly weapons is twin MG 151/20 or nothing (guns were removed in G-2/R1 or in some G-4s in order to save weight).

Agreed, only MG FF or MG 151 was used in this position. It would be impossible to load MK 108 in this orientation as there is no access from top side of the canon.