The RCBS 6.5 Creedmoor Precision Mic is an essential reloading tool that enables precise measurement of chamber headspace and bullet seating depth to 0.001-inch accuracy. This precision instrument provides spot-on SAAMI tolerance readings by measuring from the datum point on the case shoulder to the base.RCBS 6.5 Creedmoor Precision MicMeasures chamber headspace and bullet seating depth to 0.001-inch precisionDatum point to base measurement for accurate SAAMI tolerance readingsEasy-to-use design with simple twist operationExtends rifle brass life through precise measurementsAn indispensable tool for serious reloaders seeking safe accurate loads with optimal performance and extended brass longevity for their 6.5 Creedmoor rifles.