As experts in high-performance airsoft manufacturing and customization, the team at JVAN Airsoft knows that optimizing your AEG often starts with a critical component: the main spring. Selecting the right upgrade spring is one of the most effective ways to adjust your rifle’s FPS and Joule output to match field requirements. However, this process demands technical knowledge and precision. This comprehensive guide will help you understand how to choose the correct spring for your build.

Know Your Field Rules: A Essential First Step

Before purchasing any upgrade parts, your first step is thorough research. Every sanctioned airsoft field posts specific FPS (Feet Per Second) or Joule energy limits—it is your responsibility to know them. These limits are usually measured with a 0.20g BB, and exceeding them may prevent you from playing.

A common misconception is that a new gun will always comply with local field rules. Note that manufacturer-advertised FPS is only an estimate. Actual performance can vary due to production changes, barrel length, internal condition, and other factors. At JVAN Airsoft, we strongly recommend verifying your AEG’s muzzle velocity with a chronograph before game day—either at a local store or with a qualified technician.

The Role of the Spring in Your AEG

In an Automatic Electric Gun (AEG), the main spring is fundamental to generating firing power. When the gearbox cycles, it compresses this spring. The rapid release of stored energy drives the piston forward, compressing air in the cylinder that is then forced down the barrel.

Remember: the spring works alongside your compression assembly (piston head, cylinder head, nozzle, and cylinder). A weak air seal will waste energy even from a powerful spring, causing inconsistent FPS. For optimal performance, ensure excellent compression before upgrading spring power.

How to Choose the Right Spring

Springs are generally rated using the metric system. Codes like M100, M120, or S110 indicate the theoretical muzzle velocity in meters per second (m/s) using a 0.20g BB. You can interpret the number as a class of power—the higher the number, the stiffer the spring.

Here’s a general reference to help you select the right spring. Be aware: these are estimates. Actual FPS depends on your AEG’s internal setup. Always use a chronograph to confirm your output.

• For CQB/Indoor Fields (Limit: ~1 J or 350 FPS w/ 0.20g):
  For close-quarters gameplay, lower FPS is required. We recommend a spring rated below M100. An M90 or M95 spring typically yields 300-350 FPS (0.9-1.0 J), keeping you within safe limits.

• For Standard Outdoor Fields (Limit: ~1.5 J or 400 FPS w/ 0.20g):
  This is a common limit for outdoor skirmishes. To achieve 360-400 FPS (1.2-1.5 J), begin with an M110 spring. Many modern AEGs include tight-bore barrels that increase efficiency, so an M110 often offers sufficient power without exceeding limits. Always chronograph your results. If needed, step up carefully to an M120, but note that in well-sealed setups, it may exceed 1.5 J.

Durability, Warranty, and Professional Installation

An important and often overlooked aspect of spring upgrades is their impact on your AEG’s durability. Switching to a lighter spring may reduce stress on your gearbox, gears, and motor, potentially extending the life of your AEG. Installing a stronger spring, however, increases internal stress and may accelerate wear.

Also note: disassembling your gearbox and replacing parts usually voids the manufacturer’s warranty. If you lack experience working on AEG internals, we highly recommend seeking professional assistance. Proper installation is critical to safety and performance.

“Choose with confidence. A perfectly tuned spring is the foundation of consistency, and consistency is the bedrock of performance on the field”.

— The JVAN Engineering Team

Business Development

• Heidi
• JIN WANG METAL(HK) LIMITED
• Whatsapp：+8618103050072
• E-Mail :heidi@hardwareprecision.com