the bbl dosent look extended to me.
ive heard of 100 rnd mags, maybe one of them??
by the look of it, there would be no way for the notch on the front of the mag to lock in and be able to rock it back because of interferance with the bbl itself, im guessing it dosent have one, the ring on the front holds the front of the mag, and the whole thing rocks in to latch in the mag catch.
and, besides not being able to fold the stock, as mentioned, you wouldnt be ablt to put a bayo on it, so im doubting it is of russian design, they value their bayo's too much to compromise it.