Forster Headspace Gage .300 Blackout NO GO Length Rimless

Every gunsmith knows that proper use of a headspace gage is the most reliable way to test 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 and excessive headspace can be dangerous as well as impair accuracy. For instance unsupported brass fired in a rifle action with excessive headspace can rupture allowing gas to blow rearward like a rocket exhaust. Because your safety is on the line Forster Headspa