Not gonna lie that’s awesome! Only thing change would be a left side folding stock and bend the bolt knob down.Well looks like they were trying to make an "Obrez" of sorts. More for the "fun" factor than anything although I've shot a few things like this and "Fun" is not a word I'd use to describe it. I don't mind sporterizing or modernizing mil-surp rifles when done tastefully or if it's the only way to salvage an otherwise busted weapon.
This on the other hand... if it was done recently, I'd have to ask why. Mosin's aren't the ultra cheap super available rifle they once were and the tax stamps involved on this would put it into such a territory that makes no sense. I'd bet this was done a long time ago though.
Coolest Mosin pistol I've ever seen was from the YouTube channel IV8888, they named it Stumpy. Sometimes referred to as The Ugly Mosin.