Gunsmithing
Measuring Headspace[/align]


Here's how to use the tool needed to check your rifle's chamber dimensions. [/align]
By Patrick Sweeney [/align][/align]




A three-tool set of Go, No-Go gauges represents an easy way to check the headspace of your favorite rifle.[/align]
To many shooters, headspace is a mysterious term, one to which many evils can be attributed. I've had shooters come in to my shop expressing the belief that their rifles had too much, not enough, none at all and even the wrong kind--I'm still not sure what that guy was talking about. In simple terms, headspace is the dimension of the chamber of your rifle, the gap between the face of the bolt and the stopping surface for the cartridge. To be precise, it is the distance between the face of the bolt and the datum line, which is a circle of stated diameter, along the slope of the shoulder of the cartridge.
On a rimless cartridge such as the .308, the stopping surface is the shoulder. On a rimmed cartridge like the .30-30 or .303 British, the headspace is the gap for the rim. On a belted magnum, headspace is the gap for the belt. Since not every rifle or cartridge can be made to exact dimensions, with perhaps the best custom rifles being one exception, headspace is deemed to be correct if it is within a certain range.