It could be that, but it might also just be a holdover from the then-current style of stock designs, meant for rifles which didn't have a separate pistol grip. Tokarev's prototype from this same period is one of the most egregious, it's basically just an SVT with a pistol grip tacked on (and converted to 7.62x39mm, of course), leaving that part of the stock pretty much pointless
Show
I feel like the protrusion here is a bit too small, some examples of proper machine guns with stocks meant for you to hold on for contrast:
Show
Show
Show
It could be that for the prototype itself, the designers were just using existing materials (like, they just took a stock from another gun they had lying around the workshop), and this would have been changed had the gun gone further into trials - for example, Bulkin's entry starts out with a stock with a lump like Kuzmishchev's, and gets a straighter stock (much like the one the AK has) later on:
Show
Show
