Reloading 44mag

I am trying to use RCBS 44mag dies; but the resizing die is almost impossible to work. I lube my cases and have clean the die but it is so tight I can barely articulate the press. 44 mag cases are suppose to have an external diameter of .456; the die resizes down to .449 which is .007 smaller than the cases are supposed to be. Has anyone had this problem or heard of it before and if so what was done to correct the situation.