Mosin Nagant but chambered in .410 shotgun shells! This "hunting" piece is classified as a "hunting shotgun" as opposed to a rifle in Russia. Rechambering the rifle to fire shotgun shell isn't hard and it's more jerryrigging.
Other than being a standard Mosin, there are hidden rails on the sight area, using Tarkov's part.
And of course, it comes with a 5 shell .410 stripper clip.