Designed to deliver extremely precise measurements, the Hornady Micrometer Metering Insert for Pistols or Rifles allow you to make and monitor incremental changes to powder measurements, and easily return to previous settings for superior reliability. These inserts are easily interchangeable with the simple push of a button. Not compatible with Hornandy Benchrest Grade or Black Powder Measures. Deliver precise measurements Make and monitor incremental changes Easily returns to preferred settings Interchangeable with the push of a button