If you’re Googling ‘how to upgrade and lower FPS on Airsoft guns’ you’ve come across one of two problems:
- Either you’ve got to lower your Airsoft gun’s FPS to meet a field or competition limit, or
- Your Airsoft gun needs a little (or a lot) FPS
If it’s the former, you’re not alone. Most Airsoft field limits sit at around 350-360 FPS to maintain a fair and even playing field for all competitors. It’s also a safety move, to reduce the risk of serious injury on the field.
If it’s the latter, it could be that you bought a low-end Airsoft gun and you need to give it more oomph. If you’ve made any after-market alterations to your Airsoft weapon of choice, the FPS may have dropped as a result.
Whatever the reason, we’ve rounded up the most common fixes for increasing or lowering FPS. Here they are.
How to Lower FPS on an Airsoft Rifle
There are two ways to weaken your springs—the ultra-low-budget, and the mid-range:
- Grinding. This is an easy DIY method—simply fire the gun in full auto repeatedly (aim for a few hundred times) to weaken the spring. Cheap, straightforward, but it does increase the wear and tear on other parts of your Airsoft gun’s mechanism over time.
- Spring replacement. Switch out your spring for a softer type, which can be sourced through most retailers. This is an effective method of dropping your gun’s FPS without wearing down your gearbox. Moving from an M110 spring to an M90 can lower FPS by around 60 FPS.
This isn’t a trick we’d recommend, but it may work if you’re stuck in an awkward situation—like you’re on the field and you realize you’re firing over the field limit.
When you cut your spring, you run the risk of shortening the coil too much—meaning you lower the FPS too far, or you shorten the spring too far to even operate. If you must use this method, cut back half a coil rotation and check your FPS before trimming more of the spring away.
Switching From Non-Ported To Ported Cylinders
Cylinderss can be ported or unported. Ported is often called ‘vented’ and non-ported is ‘unvented’.
The first type draws air from the posterior of the piston, and the second draws air from the end of the barrel itself. Ported cylinders deliver more air flow and can lower the velocity of your bullets along with compression loss. Typically, ported cylinders are installed in general purpose Airsoft guns.
Shortening The Inner Barrel
It’s worth keeping in mind that increasing the inner barrel of your Airsoft gun to upgrade FPS may be more effective—and fool-proof—than shortening it to lower FPS. That’s because shorter barrels become extremely sensitive, and your adjustments will need to be accurate to ensure performance is what it should be.
Still want to go ahead?
If your bank balance can handle it, aim for a brass barrel or anodized aluminum—but keep in mind they’ll impact the weight of your gun.
How to Increase FPS on an Airsoft Rifle
Any Airsoft aficionado knows that the quickest—and easiest—way to upgrade your FPS is through the main spring. As the heart and soul of your Airsoft’s gearbox, altering the main spring can have a big impact.
Switching to a stiffer spring—like an M110 or M130—is effective at increasing FPS, but it means you’ll also need to replace plastic spring guides for metal equivalents (preferably one with a ball bearing).
This is because a more robust spring exerts more pressure, which requires a more resilient mechanism to hold it. If you forgo a proper bushing replacement, your plastic guide could shatter, creating shrapnel that destroys your gearbox.
You may also need to replace or reinforce the piston heads, motor, and battery to deliver full compression and avoid lock-up of your gearbox—making a spring upgrade a costly process.
Think an M130 spring won’t be enough to deliver the level of FPS you need? If you go much higher than that, expect to invest in a full gearbox replacement
Fixing Air Leaks
Inspecting your Airsoft gun around the air nozzle should make it apparent if you need to fix a leak. Leaky air nozzles reduce the effectiveness of the seal between your gun’s barrel and the gear box.
Air nozzles with an O-type inner are better for creating a strong seal, but order the best type for your specific Airsoft gun model if you need a replacement.
Switching From Ported To Non-Ported Cylinders
Ported cylinders are better for all-rounder Airsoft guns, and non-ported cylinders better for boosting FPS. In a ported cylinder set-up, the air sealing process is faster and delivers faster speeds.
Pro Tip: Like with spring guides, metal cylinders are better performers in the long-term.
Adjusting The Barrel
Another simple way to upgrade FPS on your Airsoft gun is to replace the inner barrel. Since the factory default for Airsoft guns is typically a 6.10mm barrel, you can upgrade your weapon’s FPS by replacing it with a narrower 6.03 or 6.01 mm tight bore.
Upgrading to a tight bore barrel means fitting a new hop up nub and bucking set, but capitalizes on air compression in your gun—meaning a 20 or 30 FPS upgrade and improved accuracy.
Learning how to upgrade FPS and how to lower FPS on Airsoft guns can save you a lot of stress—and hard earned money—in replacements and gun upgrades. The trick is to do it carefully, take your time, and invest in the best parts and equipment you can afford.