it makes sense in The Sopranos' realm that Artie is the only guy in the world who could do that to Tony and get away with it.

having said that, I don't buy that scene at all. it's always a terrible choice when directors and film makers don't resist and bring a shotgun or a rifle like that to a scene that absolutely doesn't need it. it reminds of that scene towards the end of "Training Day" when the spanish thug pulls a shotgun to Ethan Hawke's face to perform a simple hit. you just don't need that!