The StG45(M) was to be the replacement for the Sturmgewehr MP43 series weapons. Calculations by engineers showed an approximate 50% savings in materials and construction time per weapon with this design.
This rifle was first developed as a gas-operated delayed blowback weapon. The bolt employed 2 rollers that locked the bolt with a ramp system similar to that of the MG42. The bolt was given an opening blow by the gas piston extension which forced the rear of the bolt back, allowing the bolt face to move back and start the cycling. This rifle was called the Gerat O6, and several test models were constructed during 1944. Some employed muzzle compensators and some did not.
The Gerat 06 was built progressively, that is, sub assemblies were welded together until the rifle was complete. The receiver was a tube type design with internal reinforcing ribs and guides for the bolt to slide on. The butt contained a recess for the main spring like the MP43 series employed.
Development required by the Heereswaffe was to eliminate the gas operation of the rifle, so that it was only a retarded blowback operation. This variant was called the Gerat 06H and later the StG45(M).
The StG45(M) was pressed out of two pieces of sheet steel and the two halves then welded together. The trigger guard was part of the receiver and could not be removed or even swung away like the MP43 series. Even the grip areas were simple pressings of the trigger guard metal. The trigger group was inserted through the top opening of the breech area and locked in place by inserting the combination fire selector and safety lever. The trigger group could not be serviced as it was intended to be simply replaced in the field.
Only one StG45(M) was apparently assembled, and this was after the war by armorers at Aberdeen. According to Senich's book, they used an incomplete rifle and original Mauser drawings to make the missing parts. I have no information on how the rifle performed.
The design of the StG45(M) roller-locked action lives on in some of today's HK weapons. The CETME rifles were a direct development of the StG45(M) after the war when the designers fled Germany.
