The Precision Mic from RCBS is an essential tool for handloaders who strive for precision and safety in their reloading processes. This device offers extremely accurate measurements for chamber headspace and bullet seating depth, down to an accuracy of 0.001 inches. The Precision Mic helps reloaders ensure their brass is within SAAMI tolerances, allowing for consistent, reliable and safe loads every time. By measuring from the datum point on the case shoulder to the base, the tool helps preserve brass longevity, reducing overworking and extending its usable life across multiple reloading cycles. If you take reloading seriously, the Precision Mic is a worthwhile investment that ensures your ammunition is always in top condition. Measures chamber headspace and bullet seating depth to within 0.001 inches for precision handloading Caliper measures from case shoulder to base for saami-compliant tolerance readings Proudly made in the USA for superior quality and reliability