Russian 12.7mm/.50" grenades?

I’m reading through a book by S.V. Monetchikov called “The History of Russian Assault Rifles” (very slowly, as I’m still learning Russian), and I’ve run across mention of at least two rifles that fire some type of 12.7mm grenade cartridge; does anyone have any further information on this ammunition, as I’d believed that .50" was simply too small to get any useful sort of payload?

The TKB-059, a three-barrelled 7.62x39mm rifle with a fourth barrel in 12.7mm grenade:

The 80.002, a “side-by-side AK74”, firing 5.45x39mm from the right barrel, and 12.7mm grenade from the left barrel; this rifle ejects empty cases out of the other calibre’s magazine well, so it can only fire 5.45 OR 12.7 rounds at any one time:

Good question, it gave me already several sleepless nights.
As far as I have been able to observe in Russian media, documents, forums, collectors etc. unfortunately noone has ever reported the appearance of such a 12.7mm round.

Something does not look right with that bolt. Look at how far down the extractors are from the firing pin holes…


To get this system to work, they had to rework the bolt from the AK rotating-bolt style to a bolt that cams up and down to lock. If you imagine a chambered cartridge sitting in front of the firing pins, when the bolt carrier moves rear-ward, it would cam the bolt-head upwards (grabbing the case by the groove) and then continue rearward to extract and eject the case. A thoroughly unique design.

Regarding the Bullpup “Triple Shooter”, It is currently known as the ‘Pribor-3B’ but im not sure if that is the right designation as the word ‘Pribor’ in Russian means ‘Device’.

SDC, are you sure that TKB-059 is the right designation for the ‘Pribor-3B’?.

Secondly, Is the round thing below the barrels some Grenade Launcher?, or could it be some pack for the recoil springs?.

The explanation given in Monetchikov’s “History of Russian Assault Rifles” is that the TKB-059 is a further development of the “ZB Device”, both designed by G.A. Korobov. The “ZB Device” wasn’t made with the capability to launch grenades (see below picture), but the TKB-059 was.

ZB Device:

Interesting; Monetchikov doesn’t show a picture of Korobov’s bullpup designs, but this page ( … gneoru/65/ ) shows that they are two separate designs, with the TKB-059 based on the ZB Device. Perhaps the dovetailed piece at the front can be replaced with a separate launcher similar to the “Canary” AKSU with grenade-launcher?

The bottom thing beneath the muzzles also looks like a bayonet lug or a mount for a UGL. The launcher may be similar to the GP30 but would still like to see it though.

If that “round thing beneath the barrel” is a launcher, It could be some muzzle loaded thing that automatically cocks when the assault rifle section/barrels are used, but can only be fired when in UGL mode. The thing in front could just be some muzzle plug.

The other Pribor-3B/ZB Device/TKB-059 or whatever its called was made from various AKM type parts and has the sights offset to the left. The cocking handle is on the top of the reciever:

the dovetail below the barrel cluster is a recoil rail - firing three 7.62x39 rounds simultaneously in salvo mode would be quite an experience for a shooter without some form of recoil reduction, in that case - soft-recoiling barrels (Bren-style)