Many early automatic pistols (and some revolvers, for that matter) were offered for sale with shoulder stocks, a practice that endured up until the 1930s. Usually the factory would offer a single option, often a combination stock and holster (the “Broomhandle” Mauser is the best-known example). The Luger, however, had a remarkable number of different stock options available for owners who wanted to shoot from the shoulder.
This stock was made of sheet metal stampings and attached by replacing the grip panels of a Luger pistol. When folded, the stock added a remarkably small amount of size to the gun, which could still be fired—albeit with a somewhat awkward grip. This was done by cleverly designing the stock to consist of two layers of material that overlaid each other when folded, but could be held end-to-end when extended, providing a stock of surprisingly usable length and sturdiness. A single spring-loaded latch would lock the stock in the folded and extended positions.
Ultimately, the stock failed to be a commercial success, probably due to costs and worldwide economics in the 1920s when it was developed. Only a few hundred were made, although the serial numbers all have leading zeroes to accommodate an anticipated production number in the tens of thousands.
Despite its awkward appearance, the Benuke-Thiemann is actually quite stable and comfortable when shooting with the stock extended—although not so much when it is folded up.