This apparatus is designed to accurately measure or compare loaded or unloaded ammunition cartridges of all shapes and sizes. It measures between the base of a cartridge and any of its flat or tapered surfaces above. This apparatus is comprised of an adjustable v-block that is secured to the stem of a digital or mechanical indicator that is mounted on a vertical shaft above a flat pedestal. As the v-block and stem are raised, a cartridge case is then positioned between the v-block and the pedestal of this apparatus. The cartridge can then be engaged by lowering the v-block to contact any upper location on a cartridge. After this v-block rests on any upper location of a cartridge, the indicator is then reset to zero. The indicator is then prepared to measure or compare the difference of each cartridge in relation to its base. The measurement from the cartridge shoulder to its base is known as headspace. The measurements taken from the bullet back toward the base will reveal variations in bullet seating depth. No other tools or special bushings are required to operate this apparatus.