The AR-15 platform's popularity stems from its modularity and adaptability. However, this very flexibility necessitates meticulous attention to detail, particularly when it comes to ensuring proper headspace and timing. This is where the AR-15 Go/No-Go gauge becomes indispensable. This guide will delve into the importance of these gauges, how to use them correctly, and why they are crucial for safe and reliable operation of your AR-15.
Understanding Headspace and Timing in AR-15 Rifles
Before diving into the practical application of Go/No-Go gauges, let's briefly clarify the fundamental concepts of headspace and timing within the AR-15 mechanism.
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Headspace: This refers to the distance between the breech face of the receiver and the face of the bolt when the bolt is fully closed. Incorrect headspace can lead to catastrophic failures. Too much headspace (excessive headspace) can result in a round not properly seating, leading to potentially dangerous malfunctions. Insufficient headspace (short headspace) can cause the cartridge case to rupture under pressure, resulting in serious injury or damage to the firearm.
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Timing: This relates to the alignment of the bolt lugs with the receiver lugs. Proper timing ensures that the bolt locks securely and reliably into the receiver, preventing malfunctions and maintaining safety.
The Role of the AR-15 Go/No-Go Gauge
The AR-15 Go/No-Go gauge is a precision tool designed to measure headspace. It consists of two gauges:
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Go Gauge: This gauge is sized to the maximum acceptable headspace. If the bolt closes fully on the Go Gauge, the headspace is within the acceptable range.
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No-Go Gauge: This gauge represents the absolute maximum allowable headspace. If the bolt closes fully on the No-Go Gauge, the headspace is unacceptable, and the receiver should not be used until corrected by a qualified gunsmith.
Using the Gauges: Insert the gauge into the chamber as if it were a cartridge. Close the bolt. If the bolt closes easily on the Go Gauge but does not close on the No-Go Gauge, your headspace is acceptable.
Why Using Go/No-Go Gauges is Crucial
Using Go/No-Go gauges is not just recommended—it's essential for responsible firearm ownership. Regular checks, especially after barrel changes or significant modifications, help prevent:
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Catastrophic Failures: Incorrect headspace is a leading cause of dangerous malfunctions, including chamber explosions and bolt failures.
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Malfunctions: Improper headspace and timing can lead to misfires, failures to feed or eject, and other malfunctions, potentially compromising the shooter's safety.
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Damage to the Weapon: Consistent use with improper headspace will rapidly wear and damage crucial components of your firearm.
Choosing and Using Your Gauges
It's crucial to select gauges from reputable manufacturers who adhere to strict quality control standards. Using improperly manufactured or inaccurate gauges can provide false readings, leading to potentially dangerous situations. Always consult your owner's manual for the correct gauge size for your specific rifle.
Beyond the Gauges: Regular Maintenance and Professional Inspection
While Go/No-Go gauges are a fundamental safety check, they are not a replacement for regular maintenance and professional inspections. Regular cleaning and lubrication, coupled with periodic inspections by a qualified gunsmith, will help maintain the reliability and safety of your AR-15.
Disclaimer: This information is for educational purposes only. Always handle firearms responsibly and safely. Improper use of firearms can result in serious injury or death. If you are unsure about any aspect of firearm maintenance or safety, consult a qualified gunsmith or firearms instructor.
