The Sheridan Engineering 300 BLK Ammunition Gauge is constructed of stainless steel, and should have a functional life of over 30,000 rounds. Steel casings or dirty brass will decrease the functional life of the gauge. The gauge should be kept cleaned and lightly lubricated for storage. Prior to use, clean the gauge of any lubricant.
This gauge is manufactured to the SAAMI chamber specification using a chamber reamer. The cartridge overall length (COL) of the gauge is set to the maximum length acceptable for many common rounds. The headspace is shown by the steps in the face of the gauge. The bore of the gauge is drilled to match the bore of the barrel at the lands of the rifling.
Caliber: 300 BLK
Gauge COL: 2.260"
This gauge is designed to check brass and ammunition that has been full length resized. Brass that is neck sized only may not fit.