RCBS Small Base Sizer Die - Group A - Popular Rifle Cartridges
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. Note: Not recommended for ammunition used in bolt-action rifles.