Skip to content

How to Check the Headspace on Your AR15


What is Headspace?

Headspace is the distance between the base of the bullet and the head of the bolt. Check out this very technical drawing. 👇

Essentially, checking your Headspace helps to make sure your gun’s chamber dimensions are safe.

Watch a live demonstration to learn how to check the headspace on your AR.

Checking headspace after you build an AR or replace a barrel or bolt carrier group is a matter of safety.

Improper headspace (measuring the distance between the bolt or breech face and a known spot in the chamber where the case rests) can result in a host of issues, the most dangerous of which is catastrophic failure of the rifle. Case separations, blown out primers, failure to eject, and failure to fire are other common issues resulting from headspace failure.

The exact distance varies from one type of cartridge to another. So it is important that you take the time (doesn’t take long) to check your headspace after every build and replacement.

6 Tips for Checking Your Headspace

  1. Check headspace after every build or major component replacement: barrel or BCG, barrel extension, etc.
  2. Use quality gauges (they will run you $60 to $80 for the set).
  3. Protect the gauges from damage, they are HIGHLY accurate to within .0002 of an inch.
  4. Use the right tools for the job: we suggest a bench block, punches and needle nose pliers.
  5. If you fail a check do not fire the gun. Try a new bolt or barrel to rule out which component is the problem.
  6. Never skip this step. Most quality parts will pass this check every time, but is it worth it to find out the hard way?

Get advice from other AR*chitects and BYOAR experts!

Plus, be the first to know when we do giveaways and contests.

Leave a Reply

Your email address will not be published. Required fields are marked *