The RCBS Rifle Chamber / Cartridge Gauge is a one-piece, non-adjustable gauge designed to check chambering as well as cartridge length of your reloads. Precision made gauge checks case length, diameter, and overall cartridge length. Simply drop your loaded round into the checker and if it fits into the gauge, it'll fit your rifle. Quickly confirms whether ammunition will fit your pistol's chamber Easy-to-read engravings display caliber size With the handy RCBS rifle Chamber / Cartridge Gauge, you can confirm your cases are within tolerance for your rifle. Mfg: Rcbs