Probably one of the most important developments in submachine gun design history was the invention of a telescoping bolt. The first production SMG utilizing such bolt layout is considered the Czech Sa 23 and probably the most recognizable SMG that uses this solution is the Uzi. Thanks to the images published by the Kalashnikov Gun Magazine, today we have a chance to take a look at an early experimental Russian SMG using a telescoping bolt designed by a gentleman named Nikolay Rukavishnikov.

Rukavishnikov SMG had a collapsible stock. The telescoping portion of the bolt is exposed and has front serrations designed to provide a gripping surface for charging the gun.

The simple blowback SMGs require quite a heavy and large bolt which in its turn needs a large space to reciprocate in making the receiver of the firearm rather large despite the cartridge is very short. The most efficient solution to this problem (for simple blowback guns) was to partially extend the weight of the bolt forward, over or around the barrel. Such design solution allows to significantly decrease the receiver length making the SMG a really compact weapon.

The bolt is held on its rearmost position. Note the wear marks on the barrel where it comes in contact with the telescoped portion of the reciprocating bolt

The Rukavishnikov experimental SMG was designed in one of the Russian proving grounds and submitted to field test in 1942. As a result of the trials, this firearm was rejected. Nevertheless, it is an incredibly valuable example of firearms technologies development. The surviving sample of Rukavishnikov SMG is kept in the vault of Military Historical Museum of Artillery, Engineers and Signal Corps which is located in Saint Petersburg, Russia. According to the Kalashnikov Gun Magazine, the images of this firearm were never published before.

Images by Kalashnikov Gun Magazine