How to Lower the FPS of Your Airsoft Gun

Before we get into how to lower the FPS of your Airsoft gun, we have to understand why one has to ever consider lowering the FPS in the first place. To do that, allow me to take you on a little story about Tiny Tim. 

Tiny Tim is new to Airsoft and managed to find his way onto the RedWolf Airsoft website. He scrolls through 22 years worth of the most impeccably diverse selection of products. His eyes catch something he’s been wanting for the longest time and immediately makes the purchase. He realizes that it was a little costly and that his significant other may not approve. He’s weighed out the options and finds believes the purchase is worth the 1 month of doing dishes, laundry, and possibly sleeping on the sofa.

A week goes by and Tiny Tim stares through the peephole of his front door, eagerly awaiting the arrival of his first-ever replica. It has finally arrived! Tiny Tim throws the door open, grabs the package, shuts the door, and makes a beeline to the living room. Like a kid on Christmas day, he sheds the replica of its cardboard externals to gleam at the beautiful box inside.

The very next day, Tiny Tim is at his local indoor Airsoft field, opening the box in front of his friends. It’s the RWA KG-9 AEG, a fantastic replica of an oldies bad-guy-gun. His first instinct is to chrono it. He is stunned by the outcome as it clocks in at 330 fps on 0.2g BBs, 10 fps over the field limit. Tiny Tim is very upset by the results but ponders how one can lower the FPS. Thankfully, there are a couple of methods but only one is recommended.

Lowering the FPS of Your Airsoft Gun

In this blog, we’re going to suggest a few ways one can go about lowering the FPS of your replica, briefly go over their pros and cons, and finally, sum up why we will or won’t recommend that method. You can cut the spring, use heavier BBs, buy a different replica altogether, purchase a velocity reducer or invest in a new spring.

We will be laying out some changes you can make to an AEG and spring sniper rifles as well as gas blowback replicas. For different platforms that use different propellants such as Green Gas or CO2 or even HPA, different methods will be required to lower the FPS of your airsoft gun. We will be getting into all of these!

How to lower the FPS of AEGs and Spring Sniper Rifles

Starting off, we shall touch upon some of the most popular platforms that you might come across. Electric airsoft guns as well as spring powered airsoft guns such as airsoft snipers can usually have their FPS lowered in similar ways!

Cutting the Spring

Since Tiny Tim is at his local field, he thinks about cutting the spring bit by bit which can lower the FPS. However, this takes time as you have to constantly disassemble, cut the spring and then reassemble your replica. If he wants to take the chance, he could cut a lot more than just one coil, but then you risk cutting too off too much which could prevent the replica from functioning altogether. Different brands use different springs and coil tension so no one can really know how many coils you’ll have to snip to get the perfect fps. That being said, this is NOT one of the methods to lower the fps of your airsoft gun if you aren’t a technician.

Using a Heavier BB

Yes, using heavier BBs will lower the FPS. Unfortunately, this doesn’t alter the energy output of the BBs. This can be measured in Joules.

“the SI unit of work or energy, equal to the work done by a force of one newton when its point of application moves one meter in the direction of action of the force, equal to one 3600th of a watt-hour.”

This is a way to cheat the system but fields often have a referee there with you as you are testing the FPS of your replica. You’re required to use their BBs during testing. Once your replica is tagged as over-the-limit, you won’t be able to use it at all. Well, you can but then you’d be cheating and no one likes a cheater.

Buy A Different Replica

Obviously, this is the most expensive solution to all your problems. All websites that sell replicas will indicate the FPS the replica clocks in at. This is a great way to identify if the replica can be used in your local fields.

Import laws are a hassle when it comes to shipping as every country has specific laws. For example, Canadian import laws require replicas to clock in between 366 to 550 FPS. Anything more or less is considered illegal.

Japanese import laws require replicas to clock in under 280 FPS, which is fine for all Tokyo Marui products but not so great when it comes to other brands. 

Thankfully, there is a more affordable option to choose from.

Replacing the Spring

In the world of Airsoft, there is an abundance of aftermarket parts to choose from. More parts than there are replicas as brands like Laylax Prometheus, Modify, SHS, and many others design springs which either increase or lower the FPS if your airsoft gun. 

Knowing the spring of your replica will definitely help you out when it comes to purchasing a new spring. An example would be purchasing an M110 spring if your replica already has an M120. This will definitely reduce the FPS of your replica by 10-20 FPS and will put less stress on the internals as well.

Replacing the spring is most definitely the most affordable and recommended option. Do make sure you purchase the right spring as most companies sell replica specific springs. The last thing you want to do is purchase a spring that doesn't fit into your replica.

How About Lowering the FPS for GBB, CO2, or HPA Replicas?

When it comes to systems that are gas powered, you will need to find other ways to adjust their FPS. We have outlined a few for you and Tiny Tim.

CO2

As unfortunate as it may seem, CO2 airsoft guns (mostly pistols) won't be able to reduce the FPS due to the fact that CO2 capsules have aren't popular enough to alter their gas output. Changing out the hammer spring and adding a recoil spring will only ever-so-slightly lower the FPS, but not to a point where it is hugely noticeable.

Green Gas

When it comes to airsoft guns that use gas from a canister, where green gas reigns king though you can use duster gas which has a lower power output. This will lower the FPS of your airsoft gun by 30 or so and you will likely notice a change of performance as well. Reducing the FPS in this manner would drastically reduce recoil. What it comes down to in the end is what you consider to be more important as a player. Realism or actually playing Airsoft. Difficult choice, right?

HPA - High Pressured Air

HPA airsoft gun users are lucky as lowering the FPS can be done as easily as turning a nozzle. One of the best brands out there is Wolverine as their systems are so easy and functional. If you do have any queries as to how one can lower the FPS on a certain product, you can visit their webpage or head to their YouTube channel. Rich, the CEO of Wolverine Airsoft has some amazing guidelines on how one lowers the FPS of their replica.

Why Do Airsoft Fields Have an FPS Limit?

All Airsoft fields have a sacred duty to adhere to the rules and regulations regarding FPS, especially when it comes to the safety of their players. Before the very first game, all the replicas the players are using should take a chrono test to make sure they don't clock in over the field limit. If it's too high, they can help lower the FPS of your airsoft gun.

Letting just one replica go unchecked, shooting way over the FPS limit could cause physical harm to other players and can end up with a lawsuit to not just the player, but also the field for not following the rules.

Getting hurt is never fun. By cheating, you and the field can get into serious trouble and that just means one less field to play at every weekend. But imagine if your local field was the only field?

The horror...

Conclusion

As frustrating as it may seem, your replica clocking in at a higher FPS than your local fields allows isn't the end of the world. There are many ways to lower the FPS of your airsoft gun.

Purchasing another replica may seem like a great idea, because who doesn't want another replica? But it puts a strain on your wallet, and maybe the relationship with the spouse if you spend more than you need to.

Using heavier BBs does lower the FPS but you're cheating the system by doing so. You could cut the coils, but the process is slow, and cutting too many forces you to purchase another spring anyway. This brings me to the final point.

The best, most affordable, and most recommended option is to purchase a lighter spring designed for your replica. Companies that sell aftermarket parts dedicate their lives to knowing what your which spring does what FPS. Not all springs are the same but the FPS shouldn't differ too much. Do your homework and I'm sure you'll pick out the right spring!