The Sinclair Chamber Length Gauge helps handloaders determine the true chamber length from the bolt face to the end of the chamber's neck, potentially revealing excess case length over published trim lengths.
It is made from 12L14 soft steel to avoid damaging the chamber and comes with step-by-step instructions for repeated use.
The gauge is not suitable for use in handguns, semi-automatic, lever action, or pump action rifles and has specific caliber restrictions, such as not working with thin-necked cases like the 22 Hornet.