Hornady Modified Case 300 PRC for Lock-N-Load Overall Length Gauge
Reference B300P

These cases are specially modified to work with Lock-N-Load Precision gauges. A special fine thread is used to attach them to the gauges, ensuring that they remain perfectly square for precise alignment in the chamber of your firearm. Second, the neck of the case is made perfectly round and opened slightly to allow a standard diameter bullet to slip into the case mouth effortlessly, but concentrically, to ensure the most precise results possible.