How to Measure AR Headspace
Accurate measurement of the headspace in an AR-15 rifle is crucial for ensuring proper functioning and performance. The headspace refers to the distance between the face of the bolt and the breech face of the chamber when the bolt is fully closed. This measurement is vital for maintaining the correct fit of the cartridge case and preventing malfunctions. In this article, we will explore various methods to measure AR headspace and provide you with the necessary tools and techniques to achieve precise measurements.
Tools Required
Before diving into the measurement process, it is essential to gather the necessary tools. Here is a list of tools you will need:
- AR-15 chamber gauge
- Caliper
- Chamber brush
- Gun cleaning kit
- Headspace gauge
- Locking block
- Stud gauge
Method 1: Using a Chamber Gauge
One of the most common and straightforward methods to measure AR headspace is by using a chamber gauge. Here’s how to do it:
- Ensure your rifle is unloaded and the chamber is clean.
- Insert the chamber gauge into the rifle’s chamber, ensuring it is fully seated.
- Secure the gauge with the locking block and tighten the set screw.
- Use the caliper to measure the distance between the gauge and the breech face of the chamber.
- Compare the measurement with the manufacturer’s specifications to determine if the headspace is within the acceptable range.
Method 2: Using a Stud Gauge
Another method to measure AR headspace is by using a stud gauge. This method is particularly useful when you want to measure the headspace at different points along the chamber wall. Here’s how to do it:
- Ensure your rifle is unloaded and the chamber is clean.
- Insert the stud gauge into the rifle’s chamber, ensuring it is fully seated.
- Use the caliper to measure the distance between the gauge and the breech face of the chamber.
- Repeat the process at different points along the chamber wall to obtain a more accurate measurement.
- Compare the measurements with the manufacturer’s specifications to determine if the headspace is within the acceptable range.
Method 3: Using a Gunsmithing Bench
For a more precise measurement, you can use a gunsmithing bench. This method requires additional tools and expertise but can provide the most accurate results. Here’s how to do it:
- Set up your gunsmithing bench with the necessary tools, including a chamber gauge, caliper, and locking block.
- Secure your rifle in the bench, ensuring it is properly aligned.
- Insert the chamber gauge into the rifle’s chamber, ensuring it is fully seated.
- Secure the gauge with the locking block and tighten the set screw.
- Use the caliper to measure the distance between the gauge and the breech face of the chamber.
- Compare the measurement with the manufacturer’s specifications to determine if the headspace is within the acceptable range.
Table: AR-15 Headspace Specifications
Cartridge | Minimum Headspace (inches) | Maximum Headspace (inches) |
---|---|---|
5.56x45mm | 0.015 | 0.022 |
6.8x43mm SPC | 0.015 | 0.022 |
7.62x39mm | 0.015 | 0.022 |
Conclusion
Measuring AR headspace is an essential task for maintaining the performance and reliability of your rifle. By using the methods outlined in