Firearm Headspace is Critical to Safety

When considering firearm headspace, Shooting Times magazine offers this insight: “A practical, descriptive definition of headspace is how well the cartridge fits the gun’s chamber.” The Ballistic Assistant, elaborates on this, defining headspace as “the measurement from the breech face to the point or surface that stops the cartridge from moving forward in the chamber.”

Finally, the Palmetto State Armory’s YouTube video, “Headspacing 101” refers to firearm headspace as the “breathing room” between a rifle’s bolt face and datum on the chamber shoulder, as specified by institutions such as SAAMI or NATO. In other words, headspace is a result of the Chamber Depth, the distance between the end of the barrel and the bolt face in the assembled firearm.

Whether you call it headspace or breathing room, it doesn’t take a firearms expert to understand that a gun’s chamber depth must be precisely sized and aligned to facilitate safe, accurate shooting. In terms of safety, headspace is one of the most important measurements in a gun. Too much or too little headspace around the cartridge can be dangerous, or even fatal.

How Gun Owners Check Headspace

The typical way guns owners and custom gun smiths measure headspace is with a set of “go”, “no-go”, and field gages. To confirm proper headspace, you should be able to close your rifle when the go gage is inserted into the chamber, and be unable to close it when the no-go gage is inserted.

However, according to the Palmetto State Armory, the ability to close a rifle with the no-go gage inserted doesn’t always mean the gun isn’t safe to fire. It could just indicate that the gun is used and there is some minor internal wear. If the gun accepts the no-go gage, checking the headspace with the field gage is your next step.

If the rifle’s bolt closes with a field gage in the chamber, the headspace is over the maximum allowed for safe firing. The gun is not safe to operate, and it should be immediately removed from service until it has been inspected and repaired by a competent gunsmith.

How Manufacturers Check Headspace

The process for checking headspace, or actually chamber depth for gun manufacturers is a bit more complex. They need to check hundreds or thousands of gun barrels quickly and accurately. Dow Gage offers gages that can be built to check any caliber according to the SAAMI or NATO specification.

The company has been manufacturing precision gages since 1946. “We’ve provided gaging to the major firearms manufacturers for more than 75 years,” Dow Gage CEO Alan Ortner said. “Our skilled gage makers always ensure that the final product is of the highest quality, and that each gage produces accurate, repeatable measurements.”

The company also serves the U.S. Government’s Military Ordnance industry. Dow gages have been used to check dimensions in pistols, shotguns, rifles, and automatic weapons.

“Each industry we serve has its own standards for quality and precision, which we take very seriously,” Ortner noted. “When it comes to munitions and firearms, we know lives are at stake.”

In other words, Dow Gage leaves no headspace or “breathing room” for errors.

Contact Us for more information about precision gages to check chamber depth.