Revealing mistake: The semi-automatic handgun the gunman is shooting has no rearward slide movement after each shot is fired for the shell casings to eject. The gun is firing but it's not reloading, however it's firing several shots. This is just not possible. In a few other previous gun scenes like the Mikey Palmice hit Christopher is dramatizing the recoil by moving the handgun up and down and snapping it in a way that just doesn't make any sense. (00:48:50)
Character mistake: During an argument between Tony and Carmela, they mention her ring, given to her in earlier episode. They refer to it as an emerald. It is a sapphire.
Answer: That's not Jimmy, just a look-a-like. Jimmy's short and stout, the guy in "Christopher" episode is tall and medium built. The hair is also different.