In order to ensure you are getting the most accurate cartridge length for your rifle we offer the following tools for measuring your internal chamber length. Are you missing any tools, you can get them all together or separately here.
Copper Creek Cartridge Co. Modified Cases have the primer pockets drilled and tapped to accept a Hornady OAL Gauge. These cases and gauges are designed for finding the length that a projectile needs to be seated to touch the barrel lands.
Learn a little more about how these cases and gauges are used HERE.