Да, похоже так и есть. Смутило, что на форуме часто встречал упоминание миненгешосс в связи с БзБ.
The MG FF was adapted to fire a new type of high-capacity, high-explosive mine shell, called Minengeschoss that featured a projectile with thinner walls that allowed increased explosive charge. This projectile was lighter and generated less recoil than earlier projectiles requiring a modification of the recoil mechanism. With this modification it could fire the new mine shell, but accidentally using the heavier MG FF ammo could damage the gun. The now-called MG FF/M was introduced with the Bf 109 E-4 and Bf 110 C-4 in Summer 1940.
В общем разрывные-зажигательные в топку.