[Geek]You know where the need for this modification supposedly arose?

Tanks designed without means for CQC/infantry suppression, particularly the Elephant, a heavy tank destroyer based on spare parts of the Porsche Tiger after Henschel's design was chosen. Great armor, immense firepower, piss-poor mobility - and no MG. So they developed the "Maschinenpistolen-Vorsatz P": a weapon system to be fitted on the StG44 which allowed the crew to cover blind spots from within the tank. It consists of a barrel bent 90 degrees, a periscope, an adapter and a hull mounting.

"Vorsatz I" (or J, can't remember) used a barrel bent at 30 degrees and was supposed to be used from within open-topped APCs as well as in urban combat, though it took about a minute to put it onto your rifle and the barrel was useless after 150-300 rounds. I imagine the 45 degree version was to be used in the same manner.

Rheinmetall still have some in their collection.[/geek]

Someone knows their firearms.
If I may offer and WADR, the Krummlauf option was offered for the MG42 and the STG44 with the "I"(as was correctly stated by radx) used by the infantry and a "P"(Panzer) variant for tanks. Barrels were issued in 30, 45, 60, and 90 degree curves. The 30 was quite accurate, under 1.5 MOA, and all practically accurate. Barrel life was limited, as already stated, with the 30 degree barrels rated roughly at 300 rds and the 45 degree at approximately 160 rds. I have seen one fired and a couple on film. Truly an influential design. Kalashnikov borrowed the gas system for the AK for instance.
>> ^radx:

[Geek]You know where the need for this modification supposedly arose?
Tanks designed without means for CQC/infantry suppression, particularly the Elephant, a heavy tank destroyer based on spare parts of the Porsche Tiger after Henschel's design was chosen. Great armor, immense firepower, piss-poor mobility - and no MG. So they developed the "Maschinenpistolen-Vorsatz P": a weapon system to be fitted on the StG44 which allowed the crew to cover blind spots from within the tank. It consists of a barrel bent 90 degrees, a periscope, an adapter and a hull mounting.
"Vorsatz I" (or J, can't remember) used a barrel bent at 30 degrees and was supposed to be used from within open-topped APCs as well as in urban combat, though it took about a minute to put it onto your rifle and the barrel was useless after 150-300 rounds. I imagine the 45 degree version was to be used in the same manner.
Rheinmetall still have some in their collection.[/geek]