Carbide Sizing Die too small

This is because we have to make the sizing die small enough to resize the thinnest case to hold the smallest bullet.  Like all mass produced products, bullets and brass will vary in diameter and thickness respectively.  If we made the die the perfect size for the average bullet and case, those that fell on the small side of the manufacturing tolerance would be loose.  The expander plug in the second die will open the case mouth back up to the correct diameter for bullet seating. If you want a custom sizing die that doesn't squeeze the case mouth down as small we can provide you one, but you might run into the opposite problem (a loose bullet) with another lot of brass or bullet.