The roller-locked* Heckler & Koch G3 rifles and MP5 submachine guns have become iconic weapons of the Cold War era, being used in conflicts everywhere from civil wars in Africa, to hostage rescues and counter terror operations in Europe, to anti-cartel operations in South America. The operating system of these rifles is as unique as they are, and dates back to the death throes of the Nazi regime at the end of World War II. Desperate to save their failing state, the Nazis tasked engineers with developing new weapons, and the engineers were all to happy to oblige, lest they too be handed an old rifle and sent to the front!

One of the products of this development was the Gerät 06 created at Mauser, which mated a locking system similar to the successful MG-42 with a three piece operating rod gas system derived from the G43 rifle. This rifle offered lower cost and potentially higher reliability than the MP-44 (the “sturmgewehr”) that was then in production. As development continued through 1944, the engineers at Mauser determined that through careful control of the roller cam surfaces in the bolt, the design could be converted from a locked-breech gas operated mechanism to a delayed blowback mechanism, which simply used the mechanical disadvantage of the rollers against specially shaped surfaces to prevent the bolt from opening until pressure dropped to safe levels. This modification became the Gerät 06H, later called the StG-45(M) (“M” for “Mauser).

Some time ago at TFB, we recounted the project over at GunLab to recreate both the Gerät 06 and 06H. Now, the project has reached a major milestone with some of the first test-firings of the new Gerät 06 samples:

Three prototypes recreating different Gerät 06 developmental models are being tested:

Top to bottom: Gerät 06 2nd model, Gerät 06H/StG45(M), MP-44, Gerät 06 1st model, Gerät 06 3rd model.

*”Roller locking” is derived from terms of art used by the Germans during development (Halbstarrverriegelt, or “semi-rigid”, and Halbstarrer Walzenverschluss, or half-locked roller locking system). In this, it is similar to the term “silencer” in that it is considered somewhat colloquial today, yet was the intended term of the device’s designers!