There are a lot of variables that affect point of impact. Bullet weight is one of them. But, it's a quite a bit more complicated than just saying "heavier hits higher." Heavier bullets will hit higher than lighter rounds IF powder charges are equal. But, ultimately, it is the SPEED of the round and not its weight that affects point of impact. A heavy bullet with a big charge behind it may actually travel faster than a lighter bullet with a relatively weaker charge and, consequently, its point of impact may be lower than the lighter round.
Another factor affecting POI is barrel length. The amount of time that the round spends in the gun's barrel will affect the amount of barrel rise before the bullet exits the gun. Thus, identical rounds fired from two guns of different barrel lengths may have different POIs. At least in theory, a bullet fired from a six-inch gun may hit higher than the same bullet fired from a two inch gun. However, there is a complicating factor, that again being the speed of the bullet. The same round will have greater velocity in a six-inch barrel than in a two-inch barrel.
The bottom line is that there really is no way of predicting POI just from the weight of a round. The only way to determine POI is by firing the gun with that round. It is safe to say, however, that different rounds of different weight and powder charge will have different POIs when fired from the same gun.
