The Sinclair Chamber Length Gauge helps determine the actual chamber length of a rifle from the bolt face to the chamber's neck end, indicating potential excess case length.
Made of 12L14 soft steel to prevent chamber damage, it is used by inserting into a fired case and measuring after chambering and extracting.
Not suitable for thin-necked cases like the 22 Hornet or tight-necked chambers, except for the G-243T, and should not be used in handguns, semi-automatic, lever, or pump action rifles.