The Hornady Lock-N-Load A303 Modified Case is specially engineered for .303 British cartridges and designed to work seamlessly with Lock-N-Load Precision gauges for accurate reloading measurements.Hornady Lock-N-Load Modified Case A303 for .303 BritishSpecial fine thread attachment ensures perfect square alignment with gaugesPrecisely rounded and slightly opened neck for effortless bullet insertionMaintains concentric bullet alignment for maximum measurement accuracyCompatible with Hornady Lock-N-Load precision measuring systemEssential for precision reloaders seeking accurate cartridge overall length (OAL) measurements and optimal bullet seating depth for .303 British ammunition. Note: Dial Caliper and OAL Gauge sold separately.