The X-Sizer Die features a specially designed mandrel that eliminates the need for repeated trimming after an initial trim of .020" off the maximum case length. The mandrel contacts the case mouth during sizing and reduces the growth rate. Because of an extremely close tolerance between the mandrel and die neck wall, the neck wall of the case does not thicken as the case length is pushed back. Cases repeatedly sized in the X-Die will initially grow a few thousandths of an inch, then stabilize below the maximum case length with no discernable loss of accuracy or case life. Shellholder sold separately.Notes:Required for reloading ammunition to be used in automatic, semi-automatic, pump, slide and some lever action riflesSizes the body of cases somewhat smaller in diameter than does a standard dieSets the shoulder back slightly more than a full length sizer die to ensure proper functioning in the rifles mentioned above