The RCBS "Precision Mic" precision engineered cartridge micrometer is one of the handiest and most innovative new handloading products to come along in several years. For those handloaders seeking the best possible performance from their rifle, it provides a micrometer reading of the chamber dimension and bullet seating depth. Using a fired case the gauge gives a precise measurement of the chamber's head to shoulder dimension compared to the SAAMI recommendation. Knowing the dimension of the chamber, the handloader can then accurately set his sizing die to the best fit of cartridge to chamber. The result is not only the best performance possible with the rifle, but also longer brass life and safer loads. The micrometer function of the gauge is also applied to setting bullet seating depth at the optimum position for the best accuracy with the rifle. The gauge reads off the lands so the seating does not change with different bullet shapes. By measuring off the bearing surface of the bullet the adverse effects of variation in bullet length are minimized.