Airsoft Spring Buying Guide: What Spring for What FPS?

Introduction

Are you an Airsoft player looking to upgrade your AEG and wondering which Airsoft spring is best for your FPS needs? This comprehensive guide is designed specifically for Airsoft players considering upgrades and covers everything you need to know about choosing the right Airsoft spring for different FPS (feet per second) requirements. Whether you’re new to airsoft or an experienced player aiming to fine-tune your setup, this guide will help you select the ideal airsoft spring to optimise your gun’s performance and ensure you stay within legal limits.

Choosing the correct Airsoft spring is crucial because it directly affects your gun’s FPS, range, and reliability. Upgrading your spring can significantly enhance your AEG’s performance, but it also requires careful consideration to avoid excessive wear or legal issues. This guide will walk you through the process of selecting the right spring for your FPS goals, explain the differences between spring types, and provide practical upgrade recommendations.

Now that you understand the basics, let's look at how different springs affect your AEG's performance.

Key Terms and Definitions

Before diving into upgrades, it’s important to clarify some key terms and foundational concepts:

• Airsoft Spring: The internal component in an AEG (Automatic Electric Gun) that determines the force driving the firing cycle, directly affecting the FPS of your airsoft gun.

• FPS (Feet Per Second): Measures how fast a BB travels as it leaves the muzzle of your Airsoft gun. Many Airsoft sites use FPS during chrono testing, but the same FPS can produce different muzzle energy depending on the BB weight being used.

• Joules (J): Measures the muzzle energy of your airsoft gun. Unlike FPS, joules take both BB speed and BB weight into account, making them a more accurate way to measure power. Many UK Airsoft sites use joule limits to help ensure gameplay remains safe for everyone.

• AEG (Automatic Electric Gun): An airsoft gun powered by a rechargeable battery, using an electric motor to compress the spring and fire BBs.

Understanding these terms will help you make sense of the upgrade options and recommendations discussed below.

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AEG Springs - What Spring for What FPS?

Choosing the Right Spring

When considering an upgrade, ask yourself:

• What does my AEG lack?

• Am I seeking higher FPS, better range, or improved trigger response?

• Do I need to stay within specific site or legal FPS limits?

If you cannot answer these questions, you may not need an upgrade yet. Remember, changing your airsoft spring can raise FPS by 10–50%, but it also increases wear and may require supporting upgrades.

Legal Considerations

Before upgrading, keep these legal and safety points in mind:

• Always check your local site’s FPS limits before upgrading.

• In the UK, 370 FPS is the absolute upper limit for fully automatic airsoft guns; exceeding this can make your gun legally classified as a Section 5 Firearm.

• Many sites recommend staying below 350 FPS for AEGs to ensure compliance and avoid being turned away from games.

• Installing high-powered springs (e.g., M120 or above) in fully automatic guns is illegal and can damage your gun.

Upgrade Recommendations

For longer range or improved accuracy, consider upgrading your HOP-up rubber, bucking, and inner barrel before changing your spring. If you still need more performance, then a spring upgrade may be appropriate.

Upgrade steps to consider:

• Upgrade HOP-up and inner barrel first for range and accuracy.

• Choose a spring that matches your desired FPS and legal requirements.

• Consider supporting upgrades (e.g., high-torque motor, reinforced gearbox) for stronger springs.

• If your AEG lacks a quick-change spring system, seek help from an Airsoft Tech to avoid damaging your gun.

With these FPS values in mind, let's examine each spring type in detail.

Understanding Spring Types: M100, M110, M120, and More

Different airsoft spring types are designated by codes such as M100, M110, and M120. These codes indicate the approximate velocity (in meters per second) the spring can produce in a well-sealed AEG:

• M100 Spring: Provides around 330 FPS in airsoft guns, making it a popular choice for players who want to stay within most site limits.

• M110 Spring: Offers a higher velocity, typically resulting in about 360 FPS, but may exceed some site limits.

• M120 Spring: Typically yields approximately 400 FPS, suitable for DMR (Designated Marksman Rifle) setups that are locked to semi-automatic only.

Understanding these designations will help you select the right spring for your FPS and performance goals.

Airsoft Spring Comparison Table

Spring Type	Velocity (m/s)	FPS (0.2g BB)	Recommended Use
M85	85	280	Stock Tokyo Marui AEGs, low-power, CQB
M90	90	295	CQB, prolongs AEG life, higher ROF
M95	95	310	UK spec AEGs, balanced outdoor/CQB use
M100	100	328	1 Joule limit, most UK/JP sites, upgrade buffer
M105	105	344	Max for skirmish, tightbore barrels, may exceed 350 FPS
M110	110	360	Not advised for skirmish, close to UK legal limit
M120	120	393	DMR setups, semi-auto only, requires upgrades
M130	130	426	High-power DMR, heavy BBs, advanced upgrades

With this overview, you can quickly compare spring types and their typical FPS outputs.

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Spring-by-Spring Breakdown

M85 - 85m/s - 280 FPS on 0.2g BBs

An M85 spring, also known as an SP85, provides 280 FPS on 0.2g BBs in an AEG with an acceptable air seal. This spring is typically found in stock Tokyo Marui AEGs, keeping them in line with Japanese power regulations.

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M90 - 90m/s - 295 FPS on 0.2g BBs

An M90 spring provides 295 FPS on 0.2g BBs and is ideally suited to Airsoft AEGs intended for CQB. The additional power is not necessary for CQB ranges, and using a lower-strength spring will:

• Prolong the life of the AEG's internals

• Provide a greater rate of fire

• Improve trigger response

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M95 - 95m/s - 310 FPS on 0.2g BBs

An M95 spring provides 310 FPS on 0.2g BBs and is generally what you will find installed into most UK spec AEGs out of the box. These springs offer a balance between power and rate of fire, allowing use both outdoors and in CQB.

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M100 - 100m/s - 328 FPS on 0.2g BBs

An M100 spring, also known as a 1 Joule spring, provides 328 FPS on a 0.2g BB. This is in line with the upper limit for Airsoft under Japanese law and the advised limits for many UK Airsoft sites. M100 is a common spring strength designation, alongside M110 and M120.

Upgrade Considerations:

• Many UK sites allow up to 350 FPS, but leave a buffer to avoid being excluded from play.

• With tightbore barrels and other upgrades, an M100 spring can approach 350 FPS.

• Recommended for 350 FPS field limits, especially if you plan further upgrades.

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M105 - 105m/s - 344 FPS on 0.2g BBs

The M105 spring should provide 344 FPS on a 0.2g BB. This is the strongest spring you should install if you intend to skirmish your AEG.

Upgrade Considerations:

• Tightbore barrels can push FPS above 350 due to improved air seal.

• Stronger springs may reduce rate of fire and trigger response.

• Consider a high-torque motor for optimal performance.

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M110 - 110m/s - 360 FPS on 0.2g BBs

With an M110 spring, expect 360 FPS on 0.2g BBs in an AEG with a good air seal.

Legal Warnings:

• Not advised for skirmish; most sites will not allow AEGs above 350 FPS.

• 370 FPS is the UK legal limit for fully automatic airsoft guns.

• Exceeding this limit can result in your gun being classified as a Section 5 Firearm.

Upgrade Considerations:

• Only use if your AEG is locked to semi-auto and site rules permit.

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M120 - 120m/s - 393 FPS on 0.2g BBs

An M120 spring should provide around 393 FPS with a 0.2g BB. This spring is recommended for DMR setups, which are limited to semi-automatic only.

Upgrade Considerations:

• Requires high-torque motor and reinforced internals due to increased stress.

• Be aware of "joule creep" when using heavier BBs.

• Most sites chrono DMRs with the BBs you use—calculate muzzle energy accordingly.

Legal Warnings:

• Installing this spring in a fully automatic gun is illegal and can damage your gun.

• Always lock your AEG to semi-auto for DMR builds.

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M130 - 130m/s - 426 FPS on 0.2g BBs

An M130 spring provides around 426 FPS with a 0.2g BB. Intended for semi-automatic DMR rifles only.

Upgrade Considerations:

• Thoroughly upgrade internals before installation.

• Always chrono with the BB weight you intend to use to avoid "joule creep."

• Risk of being turned away from sites if limits are exceeded.

Legal Warnings:

• Never install in a fully automatic AEG.

• Consult with a tech to ensure compliance and reliability.

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So, that's that! You should now have a basic understanding of the different AEG springs available, what we advise using for certain roles on the battlefield, and what to consider when shopping for Airsoft gun upgrades.

If you feel like you are now ready to take the plunge, discover our Airsoft AEG spring collection, or if you're after upgrades in general, check them out via the button below!

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Summary: How Do Airsoft Springs Affect FPS and Performance?

How do airsoft springs affect FPS and performance?

• Airsoft springs directly affect the FPS (feet per second) of your gun. By upgrading to a stronger spring, you can increase your AEG’s FPS by approximately 10–50%.
• Stronger springs improve range and accuracy by increasing the force with which BBs are propelled, making them more stable in flight.
• Upgrading your spring can also enhance trigger response time, especially when paired with supporting upgrades like high-torque motors.
• However, higher-powered springs increase wear on internal components and may require additional upgrades to maintain reliability.
• Always ensure your upgrades keep your gun within legal and site FPS limits to avoid disqualification or legal issues.

By understanding how airsoft springs influence FPS and performance, you can make informed decisions to optimise your AEG for your play style and local regulations.