Any round capable of inflicting a casualty on a human is going to zip right through typical apartment building materials. Perhaps this is oversimplifying it a bit, but if you have to shoot inside your apartment, don't miss. Most JHP loadings will not through-and-through penetrate a body, or if they do, will not have sufficient energy left to still go through a wall and hit your neighbor. Also, do a "walk-through" of your apartment, determine where a missed shot will go if it penetrates a wall, and choose your "field of fire" accordingly.