Most everything you'll get on that gun was posted in the same forum in differents posts.
Here's a good brief of the designer. From http://www.riflesnguns.com/article/pribor-3b-meroka-assault-rifle
Quote:
The Pribor-3B is a Bullpup three barreled (Meroka) rifle and the Soviet rival to the U.S. Project SALVO rifle programme, but using the 7.62x39mm round used in the AK47/AKM Assault Rifles. It is also the last known derivative of the late 19th century Nordenfelt machine gun but with the capability of automatic fire.
The Pribor-3B provides 'near Minigun' firepower to increase hitting probability but suitable for a Soldier to handle. Its recoil was quite high requiring the sights to be set in a particular angle.
Cartridge ejection was behind the magazine area since the recoil force was high so the bolt traveled far back ejecting the spent cases downwards. This weapon has also led to the development of the AN-94 Assault Rifle currently in use by Russian Special Forces.
The designer of this weapon was the Russian weapons engineer German A. Korobov, who also designed the highly successful TKB-517, The TKB-408 and TKB-022 Carbines.
Hope this helps.