The M.12/P16 machine-pistol was an automatic conversion of the standard Austro-Hungarian Steyr M.12 service pistol with fire rate of about 800 rounds per minute.
By February 1916, a batch of 50 prototypes were delivered for field trials and were issued to Major Fuchs’ battalion.
These early models fed from the M.12’s standard 8-round internal magazine and, against a firing rate of 800rpm, they could only fire off a short burst or two before depleting.
This was somewhat remedied in the full production model, which extended the internal magazine to 16 rounds - an improvement, but still less than ideal.
After a successful trial phase, the M.12/P16 was accepted into service, reportedly with an order of some 5,000 units being placed.
They were issued exclusively on the Italian Front, to bolster the firepower of Tyrolean regiments fighting in the Alps. It is not known whether they were actually fielded as trench-clearing assault weapons as is commonly assumed.
Austria in 1916 was fighting a mostly defensive war against the Italians, and there is no indication that the weapon was commissioned for use by shock troops, although it is certainly possible that they were issued to some Sturmbataillons in 1917.