CLYMER 5.56 NATO 3-PIECE HEADSPACE GAUGE KIT A Brownells exclusive from Clymer. A 5.56 Headspace Gauge Kit that is perfect for your AR-15 build. This three piece kit contains a GO 1.464", NO-GO 1.4706", and a Field 1.4736" headspace gauge. These gauges have a rebated rim that allows you to use these gauges and get a accurate reading with out removing the extractor or the ejector from the bolt. Precision Machining: Each gauge is crafted from high-quality steel and machined to exact NATO specifications, ensuring accurate and reliable measurements. Durable Construction: Built to withstand repeated use, the hardened steel construction ensures longevity and co Mfg: Clymer