Lee U Carbide Small Base Sizing Dies are great for reloaders looking for ultimate feeding reliability in their handgun. These dies undersize brass between .002" and .003" smaller than other Lee Carbide Sizing dies. Ammunition with undersized brass cases will chamber each and every time it is loaded out of a magazine giving reliable chambering each time a round is stripped out of the magazine or loaded into a cylinder. Competition shooters rely on having ammunition that will feed and chamber each round of ammunition as it is stripped out of the magazine. One of the other benefits reloaders have reported when using Lee U dies is increased consistency and accuracy in loaded rounds because these dies help increase and provide more consistent neck tension on loaded bullets. The solid carbide insert inside of these dies is ground to a special contour that does not leave a belt mark on the case. These carbide dies do not require lubricant while resizing, though a little case lube will make the sizing process easier.