The Clymer 25-20 Winchester Go Gauge is essential for measuring rifle chamber length, crucial for safety and accuracy when chambering new barrels or buying used guns.
These gauges are clearly etched with "Go" or "No-Go" and caliber/gauge name for easy identification and are made to SAAMI specs.
Made of machined steel, the sizes vary with caliber and gauge style, and some gauges are interchangeable between multiple calibers within the same stock number.