556-FIELD : 5.56mm NATO Caliber Headspace Field Gauge for AR15 / M16 Armorers Kit

This high quality machined steel gauge determines overly excessive headspace in the barrel's firing chamber. This can indicate firing chamber or bolt wear.

If a rifle's bolt closes on a FIELD gauge, that means that the chamber is oversized and the rifle should not be fired. The barrel should be replaced. The Gauge is etched with caliber marking, and "FIELD" designation. Machined to SAAMI specifications.

Made in the USA.