The EGW .300 Blackout 7-Hole Cartridge Checker is a precision tool designed for reloaders and shooters to verify proper cartridge dimensions and chamber compatibility for .300 Blackout ammunition.EGW Model 70166 Cartridge Chamber CheckerSpecifically designed for .300 Blackout caliber7-hole design for comprehensive cartridge verificationPrecision machined for accurate dimensional checkingEssential tool for reloaders and ammunition quality controlThis chamber checker ensures your .300 Blackout cartridges meet proper specifications for safe and reliable feeding making it an indispensable tool for serious reloaders and competitive shooters.