One of the German oddities of the late World War II period was the German’s attempt to fire a bullet around a corner; this attachment or the StG 44 would act as a bbl. extension & changed the direction of the bullets flight, allowing the shooter to be outside of the direct fire area. Aiming was accomplished w/ the use of a prismatic sight similar to what one may imagine be used w/ a periscope. The nickname given to this device is “Krummlauf” which loosely means “Curved Bbl.” in German translated to English. There were several different degrees of curvature that were experimented w/ including 30 degree & 45 degree, but the former is the only one that ever saw realistic use. The tighter the curvature the shorter the lifespan of the bbl. would be due to the ridiculous friction that was necessary. The 30-degree bbl. had a lifespan somewhere around 300 rds. Once these were discovered & their intended purpose was verified, other countries including Russia & the United States, experimented w/ similar technology, none seeing full production. While the necessity certainly existed, the execution remained flawed but it did encourage future experimentation leading to several newer items, such as the Israeli Corner Shot, which allows the shooter to aim accurately w/o being as exposed to enemy fire.
This example includes the grenade launcher attachment & the original prismatic sighting system. This model has the gas bleed control, allowing the user to customize the amount of pressure directed out of the bore, as well as the triangular blast shield to protect he optic from escaping gasses. While the extended bbl. length when utilizing this accessory is approximately 10.5”, the overall length including the grenade launcher is a bit over 20”. The bbl. is stamped “V. G. 13” at the 12 o’clock position just rear of the front sight. The front sight is a hooded post. Blued finish on all exposed metal surfaces w/ the exception of the prismatic sight which is painted green over what appears to be a black & red base coat.