How to Lower FPS in Airsoft Guns: A Comprehensive Guide
Airsoft is a thrilling sport that simulates combat scenarios using realistic replica firearms. However, unlike real firearms, airsoft guns fire plastic BBs, and their power is measured in Feet Per Second (FPS). Maintaining the correct FPS is crucial for safety, fair play, and adherence to field regulations. This guide provides a comprehensive overview of how to lower FPS in airsoft guns, covering various methods, tools, and considerations.
Why Lowering FPS Matters
Before diving into the methods, understanding the importance of lowering FPS in airsoft is essential. Here are the primary reasons:
- Safety: High FPS can cause serious injury, especially at close range. Most fields have FPS limits to minimize the risk of harm.
- Field Regulations: Airsoft fields often have specific FPS limits for different weapon types. Exceeding these limits can result in being barred from play.
- Fair Play: Lower FPS promotes a more balanced and enjoyable game. High-powered guns can give an unfair advantage.
- Gun Longevity: Excessive stress from high-powered springs or gas systems can shorten the lifespan of your airsoft gun.
Methods to Lower FPS in Airsoft Guns
There are several methods to lower FPS in airsoft guns, each with its own advantages and disadvantages. The best method depends on the type of gun (AEG, gas blowback, sniper rifle) and the desired level of FPS reduction.
Spring Replacement (AEGs)
For Automatic Electric Guns (AEGs), replacing the spring is one of the most common and effective ways to lower FPS. Springs are rated by their power, usually indicated by an “M” number (e.g., M100, M110). A lower “M” number corresponds to a weaker spring and lower FPS.
Process:
- Disassemble the Gearbox: This requires some technical skill and knowledge of your AEG’s internals. Consult your gun’s manual or online tutorials.
- Remove the Old Spring: Carefully remove the old spring from the spring guide.
- Install the New Spring: Install the new spring onto the spring guide.
- Reassemble the Gearbox: Ensure all components are properly aligned and lubricated before reassembling.
- Test the FPS: Use a chronograph to measure the FPS after the spring replacement.
Considerations:
- Spring Compatibility: Ensure the new spring is compatible with your AEG’s gearbox and other internal components.
- Spring Quality: Invest in a high-quality spring from a reputable brand to ensure consistent performance and durability.
- Professional Installation: If you are not comfortable disassembling your gearbox, consider having a professional airsoft technician perform the spring replacement.
Gas Adjustment (Gas Blowback Guns)
For gas blowback (GBB) pistols and rifles, adjusting the gas flow is a common method to lower FPS. This can be achieved through several techniques:
- Adjustable Nozzle: Some GBB guns have adjustable nozzles that allow you to control the amount of gas released with each shot.
- Low-Power Gas: Using a lower-power gas, such as propane or duster gas, can reduce the FPS.
- NPAS (Negative Pressure Adjustment System): Installing an NPAS allows for precise adjustment of the gas flow.
Adjustable Nozzle:
If your GBB gun has an adjustable nozzle, consult your gun’s manual to locate the adjustment screw or dial. Turning the adjustment in one direction will increase the gas flow and FPS, while turning it in the opposite direction will decrease the gas flow and lower FPS. Test the FPS after each adjustment to achieve the desired level.
Low-Power Gas:
Switching to a lower-power gas is a simple way to lower FPS. Duster gas, commonly used for cleaning electronics, has significantly less power than green gas or propane and can substantially reduce the FPS of your GBB gun. However, using duster gas may affect the gun’s cycling performance, especially in colder temperatures.
NPAS Installation:
Installing an NPAS allows for fine-tuning of the gas flow. This involves replacing the original nozzle with an NPAS nozzle, which has an adjustable valve. Follow the manufacturer’s instructions for installation and adjustment. Once installed, you can adjust the valve to control the amount of gas released, thereby lowering FPS.
Barrel Length (AEGs & Gas Guns)
While not as significant as spring or gas adjustments, the barrel length can influence FPS. A shorter inner barrel generally results in a lower FPS, as the BB has less time to accelerate. However, this method is more commonly used for fine-tuning rather than making drastic changes.
Process:
- Replace the Inner Barrel: Replace the existing inner barrel with a shorter one.
- Test the FPS: Use a chronograph to measure the FPS after the barrel replacement.
Considerations:
- Accuracy: A shorter barrel may slightly reduce accuracy, especially at longer ranges.
- Compatibility: Ensure the new barrel is compatible with your hop-up unit and outer barrel.
Hop-Up Adjustment
The hop-up unit applies backspin to the BB, increasing its range and accuracy. Adjusting the hop-up can slightly affect the FPS. Reducing the hop-up can sometimes lower FPS, but the effect is usually minimal. This is more of a fine-tuning method.
Process:
- Adjust the Hop-Up: Reduce the hop-up setting on your gun.
- Test the FPS: Use a chronograph to measure the FPS after the adjustment.
Considerations:
- Range and Accuracy: Reducing the hop-up too much can significantly reduce the range and accuracy of your gun.
- BB Weight: The optimal hop-up setting depends on the weight of the BBs you are using.
Using Heavier BBs
Switching to heavier BBs can effectively lower FPS readings on a chronograph. While the actual energy output of the gun remains the same, the heavier BBs absorb more of that energy, resulting in a lower velocity. This is a common trick used to pass chronograph tests at airsoft fields.
Process:
- Switch to Heavier BBs: Use heavier BBs, such as 0.25g or 0.28g, instead of 0.20g BBs.
- Test the FPS: Use a chronograph to measure the FPS with the heavier BBs.
Considerations:
- Range and Trajectory: Heavier BBs generally have better range and are less affected by wind.
- Hop-Up Adjustment: You may need to adjust the hop-up to properly lift the heavier BBs.
Tools Needed to Lower FPS
Lowering FPS in airsoft often requires specific tools. Here’s a list of essential items:
- Chronograph: A chronograph is essential for measuring FPS accurately.
- Screwdrivers: A set of screwdrivers is needed for disassembling and reassembling your airsoft gun.
- Allen Wrenches: Allen wrenches are often required for adjusting various components.
- Pliers: Pliers can be useful for gripping and manipulating small parts.
- Lubricant: Lubricant is essential for keeping your gun’s internals running smoothly.
- Spring Compressor (AEGs): A spring compressor is helpful for safely disassembling and reassembling the gearbox.
Safety Precautions
When working on airsoft guns, always prioritize safety:
- Wear Eye Protection: Always wear eye protection when disassembling or testing airsoft guns.
- Disconnect the Battery: Disconnect the battery from AEGs before working on them.
- Empty the Magazine: Ensure the magazine is empty before disassembling the gun.
- Work in a Well-Lit Area: Work in a well-lit area to avoid mistakes.
- Consult a Professional: If you are unsure about any step, consult a professional airsoft technician.
Troubleshooting Common Issues
Sometimes, lowering FPS in airsoft can present challenges. Here are some common issues and their solutions:
- Inconsistent FPS: Inconsistent FPS can be caused by air leaks, worn-out O-rings, or a dirty barrel. Check for air leaks and replace any worn-out O-rings. Clean the inner barrel regularly.
- FPS Too Low: If the FPS is too low after making adjustments, you may need to use a slightly more powerful spring or increase the gas flow.
- Gun Not Cycling Properly: If the gun is not cycling properly after lowering FPS, it may be due to insufficient gas pressure or a weak spring. Adjust the gas flow or replace the spring with a slightly stronger one.
Conclusion
Lowering FPS in airsoft guns is crucial for safety, fair play, and adherence to field regulations. By understanding the various methods, tools, and considerations outlined in this guide, you can effectively adjust the FPS of your airsoft gun to meet the required limits. Whether you’re replacing a spring in an AEG, adjusting the gas flow in a GBB, or simply switching to heavier BBs, always prioritize safety and consult a professional if needed. Remember to always chrono your gun before heading out to the field. Happy airsofting!
