I'll answer that, in absence of Geno.
There isn't a tradition of using big bored shotguns or punt guns in Russia. You can often hear or read a story involving young hunters that couldn't hit a duck, a Grandpa with an oversized muzzleloader, stuffed with handfuls of powder and shot, shooting at a flock of sitting ducks and killing them all, followed by a very overeggagerated description of recoil - but it has every quality of a myth. The truth is, a market hunter in the old days could never afford the loads for a 8 or 4-bore, and the gentleman sportsmen genreally viewed ducks and geese as low-class, and even when they did, they preferred something else. One of the Romanovs liked waterfowling enough to write a book about it, and he used a matched pair of 12 ga London Best, with loaders.
On the other hand, there are no legal objections to using big bores. The opportunity is there, mostly for waterfowl (like anywhere else). The kind of duck hunting I do, for example, doesn't involve long walks or standing with gun in hand, so there's no reason why I couldn't use an 8-bore handy later in the season, when the birds often come in big flocks. A big bore should shine on pass-shooting geese in spring. You could also shoot a boar with one, if you had the fancy.
There's a moderate interest - most waterfowlers will tell you they wouldn't mind trying a big-bore. Yet, it will take a really rare enthusiast to actually do that. I used to know a chap that had an old big-bore double (I can't remember the gauge now, I think it was an 8 but it migtht have been 10), and he always talked about loading the brass that came with the gun and shooting it, but never did. In the 90's, someone tried to import Zabala Hermanos 10 ga.'s - but no longer does, so that should tell you something too.
Loaded 8-gauge ammo is not available, and, to my knowledge, we don't have the industrial 8-gauge. Importing live ammo of this gauge, I believe, will involve a prohibitive amount of red tape. Bringing in reloading components such as empty hulls, wads, and loading dies, shouldn't be a problem.
