Unknown page of the Frommer Stop’s history

Recently I looked at old photos of soldiers and weapons of Austria-Hungary and discovered something that had not been seen before.

Notice the unusual modification of the Frommer Stop with a body kit? What is even more mysterious – I did not find any additional information or other photos of this version of this pistol.

In themselves, the extended magazines for the Frommer Stop have long been known, there were variants for 15, 25 and 30 rounds which were used with different automatic modifications of such pistols, but it is something entirely new to see one with a stock, and not as single exemplar. I’ve read text references to the use of certain submachine guns on the Italian front by Austro-Hungarian troops. And the Dual Monarchy had many of them in own arsenal, although they did not have a variety of original solutions.

A very unusual weapon, called Pistolen-MG M.17. It is literally the Frommer Stop’s twin, as lightened as possible and adapted for firing from a special tripod mount.

“Half” of a Pistolen-MG M.17.

Automatic Frommer Stop with an extended magazine and a slightly longer barrel (most likely based on the version of the pistol for the pilots). Maxim Popenker, the famous russian researcher, many years ago showed a very similar Frommer Stop, but that was much simpler. Presumably, it is a special pistol variant for a disabled officer with damaged fingers.

Automatic Frommer Stop with long barrel and an extended magazine. Only one sample and one photo is known to exist.

I can assume that in 1917, a small batch of Frommer Stop pistols was converted to automatic fire, equipped with an expanded magazine and butt, which were used in Jagdkommando – the Austro-Hungarian equivalent of legendary german Stoßtruppen, i.e. assault units.

The original photo, which was the cause of this micro-note.

Does anyone have any details on this enigmatic version of the Frommer Stop? Please share information if you know something.