Lyman Multi-Caliber Small Rifle Ammo Checker Cartridge Gauge 204 Ruger, 22 Hornet, 223 Remington, 22-250 Remington, 300 AAC Blackout, 7.62x39mmLyman's Ammo Checkers check the quality and consistency of both reloaded rounds and purchased ammo. A must for any auto shooter for easy and consistent feed. You can't afford misfeeds, so get the easiest "no go" gauge available today! These Ammo Checkers are gauges that allow a reloader to quickly confirm that their ammunition will fit in their chamber. Machined from solid blocks of 6061 T6 aircraft grade aluminum and cut with custom tooling to SAAMI