Introduction
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The AR-15, a rifle celebrated for its modularity and versatility, has become a cornerstone of modern firearms ownership. However, its widespread appeal necessitates a firm understanding of its mechanics, particularly regarding safety. One critical aspect often overlooked, yet paramount to the proper and safe functioning of an AR-15, is headspace. The headspace of an AR-15 is much more than a technical detail; it is the foundation upon which accuracy and, crucially, the shooter’s safety are built. Neglecting or misunderstanding the concept of headspace can lead to a spectrum of problems, ranging from minor malfunctions to catastrophic failures that could result in serious injury.
Definition and Overview
This article delves deep into the process of checking and understanding *how to headspace an AR-15*. It provides a comprehensive guide for gun owners, enthusiasts, and anyone looking to deepen their knowledge of their AR-15. We will explore the critical components, the tools required, the step-by-step procedures for inspection, and the significance of the results. This knowledge empowers you to not only maintain your firearm effectively but also to identify potential issues before they escalate into dangerous situations.
Understanding the Core Components
Before diving into the process, it is vital to grasp the key components involved in headspace. These parts work in unison to ensure the safe and efficient firing of the AR-15.
The Bolt
The bolt is the heart of the AR-15’s locking mechanism. It is a robust component containing the firing pin, the extractor, and the all-important bolt face. The bolt face is the surface that directly contacts the base of the cartridge. It is the starting point from which the measurement for headspace is taken. The extractor, a small but critical part, hooks onto the cartridge’s rim to pull the spent casing from the chamber after firing.
The Barrel Chamber
The barrel chamber is the area within the barrel that houses the cartridge. The chamber is precisely machined to accommodate the specific cartridge type for which the rifle is designed. The dimensions of the chamber are crucial for headspace. A chamber that is too short or too long will cause problems when the cartridge is loaded. The chamber’s length is determined by the barrel manufacturer, and it’s part of the barrel’s specifications.
The Barrel Extension
The barrel extension is an integral part of the barrel. It’s a steel component containing the locking lugs, which engage with the bolt lugs to secure the bolt in place during firing. The barrel extension is attached to the barrel and must be precisely aligned to ensure the bolt locks correctly. Its interaction with the bolt is key to safe and accurate operation.
The Bolt Carrier Group (BCG)
The bolt carrier group (BCG) is the heart of the AR-15’s operating system. This assembly is the group of parts that allow the rifle to operate. This includes the bolt, bolt carrier, firing pin, firing pin retaining pin, and cam pin. The bolt carrier group houses and guides the bolt through its locking and unlocking motions. During firing, the BCG absorbs the recoil energy.
Types of Bolts
Different types of bolts can be found on the market. The bolt must be compatible with the cartridge being used. For example, there are bolts for .223 Remington/5.56x45mm NATO, .300 Blackout, and other calibers. It is essential to select the right bolt to operate your AR-15 safely and correctly.
Tools and Materials You Will Need
Performing a headspace check requires specific tools and materials. Having these items readily available will make the process easier and more efficient.
Headspace Gauges
Headspace gauges are precision tools designed to measure the distance between the bolt face and the shoulder of the chamber. These gauges are available in sets, and each set includes three gauges.
Go Gauge
A Go gauge is slightly shorter than the correct headspace dimension. When the bolt closes completely on a Go gauge, it confirms that the headspace is at or above the minimum acceptable length.
No-Go Gauge
A No-Go gauge is slightly longer than the correct headspace dimension. If the bolt does not close completely on a No-Go gauge, it confirms that the headspace is within acceptable limits.
Field Gauge
A Field gauge is the longest gauge. If the bolt closes on a Field gauge, the headspace is beyond the safe limit, and the firearm should not be fired until the issue is resolved.
Additional Materials
You will need a complete BCG. If you are assembling an AR-15, having all BCG parts in their respective places is a necessity to proceed.
Other tools may include a torque wrench, a vice, and a barrel vise. These tools may be necessary when replacing a barrel. A torque wrench is essential to ensure proper tightening of the barrel nut. A vice will hold the receiver, and a barrel vise will hold the barrel.
Conducting a Headspace Check on an Assembled AR-15
Safety is paramount when working with firearms. Before you begin, make absolutely certain that the rifle is unloaded. Visually inspect the chamber and magazine well to ensure they are empty. Always wear appropriate eye protection. If in doubt, seek guidance from a qualified gunsmith.
Preparation
Begin by ensuring that your AR-15 is unloaded. Remove the magazine and physically inspect the chamber to confirm that no round is present. Open the bolt and visually check the chamber to verify that it’s clear of any ammunition.
The Go Gauge Test
First, insert the Go gauge into the chamber. Close the bolt. The bolt should fully close and lock. If the bolt closes completely, the headspace is at least as long as the Go gauge, which is within minimum specifications.
The No-Go Gauge Test
Next, insert the No-Go gauge into the chamber. Close the bolt. The bolt should not close completely on the No-Go gauge. There should be resistance. If the bolt closes completely, the headspace is potentially too long.
The Field Gauge Test
Optionally, you can use a Field gauge. Insert the Field gauge into the chamber and try to close the bolt. If the bolt closes on the Field gauge, the headspace is too long, and the rifle may be unsafe to fire.
Interpreting the Results
Interpreting these results is critical. If the Go gauge closes, and the No-Go gauge does not close, the headspace is within the acceptable range. The rifle is safe to fire. If the bolt closes on the Field gauge, your headspace is excessive. It is imperative to seek professional gunsmithing advice immediately. If the bolt does not close on the No-Go gauge, then the headspace is too short. The rifle will likely experience a malfunction.
Addressing Headspace Issues
The results of your headspace check determine your next steps. If everything checks out, that’s great! If not, then it is time to problem solve.
Within Specification
If the headspace is within specification, congratulations! Your rifle is within safe operating parameters. No further action is required. However, it is a good practice to periodically recheck headspace during the life of the firearm.
Too Short
If the headspace is too short, it could be caused by a tight chamber or incorrect parts. Consult with a qualified gunsmith to determine the root cause. The gunsmith may need to ream the chamber to correct the headspace. Never attempt to modify the chamber yourself, as this requires specialized tools and expertise. Improperly modifying the chamber can create a dangerous situation.
Too Long
If the headspace is too long, this indicates that the distance from the bolt face to the shoulder of the chamber is too large. Causes can include excessive wear on the barrel, or the use of incorrect parts. A worn barrel may need to be replaced. If this is the case, consult with a gunsmith immediately. Attempting to shoot a rifle with too much headspace is very dangerous. It can lead to ruptured cartridge cases and severe injury.
It is imperative not to attempt to modify the chamber or barrel yourself. These are precision components that require specialized tools, skills, and experience. Working on them without the correct training can create dangerous situations, which can lead to serious injury, or even death.
The Implications of Assembly
When building an AR-15, headspace is one of the final steps. The best thing to do is assemble the lower receiver. Then, assemble the upper receiver, but do not fully assemble the BCG.
After the BCG is complete, place the bolt into the barrel extension. Test the headspace. If the headspace checks out, then the BCG can be assembled completely.
Conclusion
Understanding *how to headspace an AR-15* is a vital component of responsible firearm ownership. It is crucial for accuracy, safety, and the longevity of your firearm. This guide provides the necessary information to perform a basic headspace check.
Always remember, safety is paramount. This article provides a guide to inspecting the headspace of an AR-15. This guide is not a substitute for professional gunsmithing services.
Seek professional help from a qualified gunsmith or armorer if you encounter any issues. Working with firearms requires a commitment to safety and proper procedures. Do not hesitate to seek expert advice if you are unsure of any step. Your safety, and the safety of those around you, depends on it.
Resources
For further information on *how to headspace an AR-15*, explore these resources:
Websites and forums dedicated to AR-15 building.
Books from reputable publishers on gunsmithing.
Professional gunsmithing manuals.
Headspace gauge manufacturers.
Always prioritize safe gun handling practices and never compromise on safety.
