Ask Ian: What is Headspace? (And Why It Matters)

Published on December 16, 2022
Duration: 12:17

Headspace is the critical measurement of free play a cartridge has within a firearm's chamber, essential for safe and reliable operation. Incorrect headspace, whether insufficient or excessive, can lead to dangerous malfunctions like extraction failures, case bulging, or catastrophic case head separation. Proper headspace is particularly important when dealing with military surplus firearms or custom builds from parts kits.

Quick Summary

Headspace is the measurement of free play a cartridge has within a firearm's chamber. It's critical for safety and function, ensuring proper support and reliable extraction. Insufficient headspace can cause high pressures, while excess headspace risks case stretching and separation.

Chapters

  1. 00:00Introduction to Headspace
  2. 00:25Defining Headspace and Case Function
  3. 01:34How Proper Headspace Works
  4. 02:38Risks of Insufficient Headspace
  5. 04:32Dangers of Excess Headspace
  6. 08:17Headspace on Military Surplus Rifles
  7. 10:30Setting Headspace on Kit Builds

Frequently Asked Questions

What is headspace in a firearm?

Headspace is the measurement of the free space a cartridge has within the firearm's chamber. It's critical because it ensures the cartridge is properly supported when fired and allows for reliable extraction after firing.

What happens if a firearm has insufficient headspace?

Insufficient headspace means the chamber is too short or the bolt closes too far. This can jam the cartridge into the rifling, causing dangerously high pressures and potential extraction failures or firearm damage.

What are the risks associated with excess headspace?

Excess headspace allows the cartridge case to stretch excessively backward upon firing. This can lead to case bulging or, more dangerously, catastrophic case head separation, which can damage the firearm and injure the shooter.

Why is headspace important for military surplus guns?

Many military surplus rifles have undergone repairs, sometimes involving bolt replacements. Mismatched bolts can alter headspace, making it crucial to check before firing to ensure safety and prevent malfunctions.

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