Forster .243 Winchester SAAMI Dimensioned Field Length Rimless Headspace Gauge

Every gunsmith understands that the proper use of a headspace gage is the most reliable way to measure the length of a rifle chamber. "Headspace" is the distance between the face of the breech and the base of the cartridge when the action is closed. Excessive headspace is not only dangerous but can also compromise accuracy. For example, unsupported brass fired in a rifle with excessive headspace can rupture, causing gas to blow rearward with explosive force, much like rocket exhaust. Because you