The Sinclair Shoulder Bump Gauge Insert #26A is a precision reloading tool designed for accurate cartridge case shoulder measurement with a 26-degree angle and 6mm specification.Sinclair Shoulder Bump Gauge Insert #26A26-degree angle measurement6mm specification for precise fittingCompatible with Sinclair bump gauge systemsPrecision-machined for accurate case shoulder measurementEssential for serious reloaders who need consistent cartridge case preparation and shoulder positioning for optimal accuracy and reliable chambering.