Whether used for a .223 Remington or .308 Winchester, the RCBS X Die Full Length Die Set is an excellent choice for reloading. What makes this particular die set so special is the mandrel that eliminates additional trimming after the first trim of 0.02 inches off the maximum length of the case is complete. During sizing, the mandrel comes into contact with the case mouth, which in turn cuts down on growth rate. In addition, there is no thickening of the neck wall, as the case is pushed back because of the extremely close tolerance between neck wall and mandrel.