For optimal safety and precision, Lyman strongly recommends inspecting all resized bottleneck rifle cases to ensure they maintain proper headspace dimensions. Lyman's case length/headspace gauge is the most reliable way to verify this critical measurement. Simply insert your resized case into the gauge, and it will confirm that the headspace falls within the correct range, neither exceeding the maximum nor dropping below the minimum tolerance. The gauge also identifies cases that exceed the maximum permissible case length. Should any case show excessive headspace, dispose of it immediately. Lyman's case length/headspace gauges remove any uncertainty, offering reloaders a dependable solution for perfect reloads every time. Verifies case headspace Detects instances of prolonged duration