The Sinclair Shoulder Bump Gauge Insert #20 is a precision reloading component designed for accurate shoulder measurement of .308 cartridge family cases with a 20-degree shoulder angle.Sinclair Shoulder Bump Gauge Insert #2020-degree shoulder angle specificationCompatible with .308 cartridge familyPrecision machined for accurate case measurementEssential tool for consistent handloadingThis insert enables reloaders to achieve consistent case shoulder positioning for improved accuracy and proper chamber fit in .308 family firearms.