Headspace, the critical clearance between the cartridge case head and the chamber of a firearm, is paramount to safe and reliable operation. Insufficient headspace can lead to catastrophic malfunctions, while excessive headspace compromises accuracy and can cause dangerous pressure increases. This is where the go/no-go headspace gauge comes in. This essential tool allows firearm owners and professionals to quickly and accurately assess the headspace of their firearms, preventing potential accidents and ensuring optimal performance.
Understanding Headspace and Its Importance
Headspace refers to the distance between the breech face of a firearm and the head of a cartridge when the round is chambered. This dimension is meticulously specified by the firearm manufacturer and must fall within a precise tolerance. Too little headspace (undersized) can result in the cartridge failing to chamber completely or becoming stuck, potentially causing a dangerous malfunction. Conversely, excessive headspace (oversized) allows the cartridge to move too far back into the chamber, leading to:
- Reduced accuracy: The bullet may not be properly aligned with the barrel rifling.
- Increased pressure: The excessive rearward movement can cause dangerously high chamber pressures, resulting in a potential catastrophic failure of the firearm.
- Damage to the firearm: Consistent firing with excessive headspace can damage the breech face and other critical components.
How a Go/No-Go Headspace Gauge Works
A go/no-go headspace gauge is a simple yet crucial tool consisting of two gauges:
- Go Gauge: This gauge represents the minimum acceptable headspace. It should chamber smoothly and easily.
- No-Go Gauge: This gauge represents the maximum acceptable headspace. It should not chamber completely. If it does, it indicates excessive headspace, requiring immediate attention.
These gauges are precisely manufactured to the manufacturer's specifications for a specific firearm cartridge combination (e.g., .308 Winchester, 9mm Luger). Using the wrong gauge can lead to inaccurate and potentially dangerous assessments.
The Checking Process: A Step-by-Step Guide
- Safety First: Always ensure the firearm is unloaded and that the chamber is clear before using any gauge.
- Gauge Selection: Choose the correct go/no-go gauge set for the specific cartridge caliber of your firearm.
- Insertion: Insert the go gauge into the chamber. It should slide in smoothly and easily. If it encounters resistance, there might be an issue that needs investigation beyond headspace.
- Go Gauge Result: If the go gauge chambers smoothly, it indicates that the headspace is within the minimum acceptable range.
- No-Go Gauge Insertion: Now, carefully insert the no-go gauge. It should not chamber fully. If it does, it signifies excessive headspace.
- No-Go Gauge Result: If the no-go gauge chambers fully or partially, this is a serious indication of excessive headspace. The firearm should not be fired until the issue is addressed by a qualified gunsmith.
When to Use a Go/No-Go Headspace Gauge
Regular headspace checks are crucial for maintaining firearm safety and accuracy, especially after:
- Replacing a barrel: A new barrel might not have the precise headspace dimensions.
- Significant use: Repeated firing can gradually wear down firearm components, potentially affecting headspace.
- After a malfunction: If a firearm malfunctions, checking headspace is a critical troubleshooting step.
- Purchasing a used firearm: Always verify the headspace of any used firearm before firing it.
Finding and Using Your Go/No-Go Gauge
Go/no-go headspace gauges are readily available from reputable firearm accessory suppliers. It’s essential to ensure you purchase gauges from a trusted source to guarantee accuracy. Always carefully follow the instructions provided with your gauge set.
Conclusion
The go/no-go headspace gauge is an indispensable tool for responsible firearm owners and professionals. By ensuring proper headspace, you drastically reduce the risk of catastrophic malfunctions and maintain the accuracy and reliability of your firearms. Regular inspection using this simple yet critical tool is a vital part of safe and responsible firearms handling. Remember, safety should always be the top priority. If you're unsure about anything, consult a qualified gunsmith.
