The RCBS 30-06 Springfield 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 measures from the datum point on the case shoulder to the base providing reloaders with spot-on SAAMI tolerance readings.RCBS 30-06 Springfield Precision MicDetermines chamber headspace and bullet seating depth to 0.001-inch precisionMeasures from datum point on case shoulder to baseProvides accurate SAAMI tolerance readingsEasy operation with just a few twistsAn indispensable tool for creating safe accurate loads while extending the life of your rifle brass. Perfect for serious reloaders who demand precision and consistency in their ammunition preparation.