So this revolver seems to be a one of a kind pistol. I have to admit I'm somewhat bemused by the long barrel on it. The Nagant revolver uses a cartridge nearly as long (7.62x38 versus 7.62x39), but the barrel is only around 4 inches and the cylinder is nowhere near that big.
Interesting concept gun, but it seems sort of impractical even for a survival pistol meant to be compatible with a 7.62 ComBloc rifle. In my opinion, you'd be better off with a Circuit Judge as your longarm and a 4 inch barreled Taurus revolver (I think they call it the Tracker?) that was sort of the precursor to the Judge pistol line, both chambered for .45 Colt (aka .45 Long Colt, as I grew up hearing it) and .410 shotshells.