Can't be helped.
A standard shellholder is .125" deep, no conventional die can touch that at all, and the die mouth is radiused so you can get the case started easily, so that much is not sized either. It is not really a belt, it is just the part of the case that is not, cannot be resized in a press. Hardly ever causes trouble unless you have one of those so-called "minimum match chambers" and try to use pickup brass in it.
There are push through and roll size machines that will resize the whole case but they are kind of expensive specialist equipment and should not be necessary for standard loads in a standard gun. Easiest to use a cartridge gauge and demote those that fail to practice; they will usually still chamber although I will not use them for a match.