Every gunsmith understands that the proper use of a headspace gage is the most reliable method to test 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 and excessive headspace can be both dangerous and detrimental to accuracy. For example, unsupported brass fired in a rifle with excessive headspace can rupture, causing gas to blow rearward like rocket exhaust. Your safety is Paramount, which is why Forster Headspace Gages are meticulously crafted with precise manufacturing standards to ensure accurate testing of your rifle's chamber. If a rifle closes on a FIELD gage, it indicates that the rifle chamber is dangerously close to or has already surpassed the SAAMI specified maximum chamber size, highlighting the importance of proper headspace measurement for safe and reliable firearm performance.