13mm: Nur fur ungesteuerte Bordwaffen

I saw pictures of a wooden ammo box marked for 13mm Pzgr. Patr. L’spur El. o. Zerl and dated 15.10.43. One of the labels has the subject phrase, “Nur fur ungesteuerte Bordwaffen” which I loosely translate as “only for uncontrolled aircraft weapons.” but I can’t figure out what this really means. As the 13 X 64B round was electrically primed, I believe it was to be used in “controlled” weapons, i.e. at least controlled enough to be synch’ed, or there would be little use for the electric priming and firing systems. So, what does “uncontrolled” mean in this context? Perhaps something like an observer’s gun with “free” aiming vs. a fixed weapon mounted in the nose and “controlled” by the pilot aiming the airframe? Any input would be appreciated.

The MG131 was used both in synchronizer-utilizing roles and roles where there was no need for synchronizing.

Gesteuerte = synchronized
Ungesteuerte = not synchronized

The ammunition used in sync. purposes was to my knowledge the more even loaded lots, from testing. The “good” lots were marked for use in the sync. guns, the “bad” lots were marked for use only in unsync. guns.

Examples for sync. gun would be a nose, cowling, or wing root mounted pair of guns on the Bf-109 or Fw-190, shooting through the propeller. In addition the electrical ammunition counter would work better (more accurately) with good and even ammunition. These German ammo counters were rather simple and “counted” ammo as the trigger was held down.

Examples for unsync. gun would be a nose, belly, or tail mounted gun on a bomber, e.g. Ju-88 or He-111, where there was no need for the gun and ammo to be synchronized, as they did not shoot through propellers.

Obviously, the “only” marking is because one wouldn’t want to shoot ammo that potentially could lead to a propeller strike and potential catastrophical failure of the propeller and/or engine.

As far as I remember reading (in German, not my first or second language) they were strict on issuing the sync. ammo only for sync guns.

More can be found here I believe: L. Dv. 4000/10, " Munitionsvorschrift für Fliegerbordwaffen".
Hope this was somewhat helpful.



THANKS much. Danke


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No problem Taber.


Probably not relevant to this question, but might be of interest: Rheinmetall-Borsig did design and make some examples of the MG 131 which used percussion-primed ammunition. As far as I know, none got into German service but this version was adopted for Japanese Navy aircraft as the 13mm Type 2, used only in flexible mountings I believe.