This is a reposting of a video from September 2016 with a new introduction. The recent publication of the new and expanded edition of Hans-Dieter Handrich's book "Sturmgewehr!" has revealed new information about the history of this rifle which I wanted to put into the video.
For the record, this rifle sold for $63,250 back in September 2016: http://www.rockislandauction.com/viewitem/aid/68/lid/1448
German arms development during World War II was quite the chaotic mess, in many ways. This Gustloff rifle program was initialed after a June 1942 meeting at which Hitler authorized continued development of the Maschinen Karabiner concept on the condition that it was done with the 8x57mm cartridge. Of course, this was doomed to failure, because the concept required easily controllable fully automatic fire from the shoulder, which was simply not possible with 8x57mm. However, the program to develop a stamped, select-fire MKb was contracted to the Gustloff firm anyway.
There were several reason why this was done. First, it would give cover to the continued 8x33 MKb-42(H) development since a rifle-caliber weapon was also now in development. Second, when it inevitably performed poorly at accuracy trials, it would make the 8x33 rifles look good by comparison. Third, by giving the well-connected Gustloff company a development contract, it would relieve some political pressure on the ordnance department. The expected trials never happened, though, because by January of 1943 it was clear that the rifle would take far too long to have ready for production, and the program was cancelled.
Two versions of the weapon were made by Gustloff, refered to by the company as the model 206 (semiauto only) and 208 (selective fire). they were largely sheet metal rifles with a gas piston operating systems and an unusual vertically traveling locking block, akin to the Type 94 Nambu and Bergmann 1910 (as well as the much more recent Arsenal Strike One). They were fed from MG-13 box magazines - cut down from 25 rounds to 10 rounds capacity on this example.
For more information on the development and context of the Sturmgewehr rifles, I highly recommend "Sturmgewehr! From Firepower to Striking Power" by Hans-Dieter Handrich: http://www.collectorgrade.com/bookshelf10.html
Cool Forgotten Weapons merch! http://shop.bbtv.com/collections/forgotten-weapons