RCBS - Small Base Sizer Die 325 Winchester Short Magnum (WSM) - 31631
Note: Not recommended for ammunition used in bolt-action rifles.
The Small Base Sizer Die is for bottleneck type cases used in tight-chambering semi-automatic, pump or lever-action firearms. The sizer resizes cases below SAAMI minimums, reducing the shoulder and body by a few thousandths. It also de-primes the case.