Frankford Arsenal, Platinum Perfect Hand Primer WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov. Works with both small and large primers Quick thumb release system Adjustable seating system The Frankford Arsenal Perfect Seat Hand Primer will make sure you do not over seat and crush a primer again. It features a dial that adjusts the seating depth .001 at a time with a total adjustment range of .05. Once you have the seating depth set, you can squeeze the handle as hard as you want; with the positive hard stop the primer will never seat deeper than the set depth. The Frankford Arsenal Perfect Seat Hand Primer, designed so you can have the perfect primer seat every time.