Forster .257 Roberts SAAMI Dimensioned Go Length Rimless Headspace Gauge

Every gunsmith understands that using a headspace gage is the most reliable method for testing the length of a rifle chamber. "Headspace" refers to the distance between the face of the breech and the base of the cartridge when the action is closed. Excessive headspace can be dangerous and negatively impact accuracy. For example, unsupported brass fired in a rifle with excessive headspace may rupture, causing gas to blow rearward like rocket exhaust. Because your safety is at stake, Forster Heads