TKB 0145 Adov Prototype Rifle

Super rare experimental rifle that uses prototype SC129 12.7mm ammo.
Like literally there is just one image of it from V.S. Katarzhnov book that say it's based on early version of TKB-0145 rifle, and it was probably developed as part of experimental work on weapon system that later end with creation of SHAK-12 rifle.
No more info is available, even name, as on side of it there is just red writingТКБ-0145 ЦКИБ СОО А.Б. Адовым so the name of the gun is based on.