Ultimate Guide to Airsoft Hop Up

Airsoft Range & Accuracy


In today’s world of technology, airsoft hop up system is a must for the airsoft guns. In the old days, hop up system was not incorporated in the airsoft guns and therefore, the guns were less efficient with infrequent accuracy.

Today as the technology has developed by a vast leap, so has the mechanism for the airsoft gun. Now Airsoft range and accuracy have increased vastly due to the introduction of mechanical systems such as hop up system.

So let’s talk about the range and accuracy of the airsoft guns a bit.

Airsoft Range and Accuracy

The range and accuracy of an airsoft gun depend on a few things. Many of you people (not everyone) might think that the higher the fps, the further your BB shot will go. But that’s not the case at all!

Power is not always everything. But the power of science is!!

If you can utilize the rules of nature to your advantage accordingly, then you’ll be able to accomplish so many things which will seem like a miracle or magic.

But enough with science and miracles.

Right now we are discussing airsoft range and accuracy.

What are The Main Factors for Airsoft Range and Accuracy?

Airsoft range and accuracy depends on the 3 most important factors.

They are –

  1. Consistency
  2. Barrel
  3. Hop Up


So what is consistency in airsoft?

Shooting over and over again without taking a break?

Continuous shooting on the same spot?

It’s nothing like that actually!

Consistency in airsoft actually means that the gun will shoot BBs at the same rate. If every time you shoot with an airsoft gun, the BB comes out from the barrel with different output power, then that means the gun lacks consistency.

When the gearbox your airsoft replica posse a vast fps margin, that means the output speed would vary.

The gearbox is what is used for shooting BBs from your airsoft gun. A gearbox consists of gears, spring, spring guide, cylinder, cylinder head piston, piston head, etc.

When the BB speed becomes unpredictable, then the shooting range and accuracy is no longer predictable as well. But if you have a consistent BB speed, then the range of and airsoft gun will become consistent as well depending on external elements like the wind.

If you can determine the speed and range for your weapon, you would certainly be able to shoot more accurately.

In short, Less FPS Variation = More Accuracy

Airsoft Hop Up
Airsoft GearBox


The barrel of your airsoft gun is no less important than the gearbox.

Certainly, the gearbox is a very important factor for shooting speed and range because this is the mechanism that’s used to shoot BBs from an airsoft gun. But you also have to consider another thing. That is the barrel from which airsoft ammunition comes out from.

If there is something wrong with the barrel then it will obviously influence the speed and range.

The imperfect barrel which has a very rough surface inside or may have a bend will have an impact on your weapon’s performance considerably.

For example, a wide bore barrel would not be as accurate as a tight bore barrel due to air pressure. You can upgrade your airsoft gun by using a slightly smaller bore barrel.

Since the air pressure used for shooting is compressed inside the barrel, it will increase if the barrel gets tighter. Due to the compression, the air pressure increases inside a tight bore barrel compared to a wide bore barrel and this causes the fps of BBs to increase as well.

Finally, we have reached the topic at hand.

Yes, we’re going to explain about Hop Up. Since this is actually the topic we are here to learn today, the explanation will be given thoroughly compared to other 2 factors of airsoft range and accuracy.

Airsoft Barrel
Airsoft Barrel

What is Airsoft Hop Up?

Hop Up is short for High Operation Power. As the name suggests, the airsoft Hop Up system truly increase the operation power of an airsoft gun.

It’s actually a small mechanical part installed inside the barrel of your airsoft gun to apply backspin on the BBs when shot and increase the range & accuracy significantly.

How does Airsoft Hop Up work?

The airsoft hop up the device is located on the top side of the inner barrel of an airsoft gun. It works as a friction pad (called bucking) for the airsoft BB. When the BB is shot by the airsoft gun, it passes through the barrel where this hop up part is located.

As the BB is passing through the barrel, it rubs against the friction surface. Since the friction surface i.e. airsoft hop up is on the upper part of the barrel, the BB gets a backspin as it is shot out.

This backspin results in a longer range for BBs. The backspin of a BB pallet deflects the air surrounding it and increase the range via a phenomenon called Magnus Effect.

The GIF animation below is a representation of a BB pallet acquiring backspin due to airsoft hop up,

Hop Up Animation
Hop Up Animation

What is the Magnus Effect?

Magnus Effect is a phenomenon observed in a spinning object moving through the air or any liquid substance.

When a spinning cylinder or spherical object moves straight through a fluid (gas or liquid), its path deviates from the trajectory according to the nature of its spin. This phenomenon is called the Magnus Effect.

History of Magnus Effect

The name Magnus Effect came from a German physicist named Heinrich Gustav Magnus. He was the first person to be credited for describing this phenomenon in detail. But he was not the first one to notice or describe the event. In 1672 Sir Isaac Newton was the first to describe the phenomenon.

While he was watching a tennis match in Cambridge, he saw the spinning ball curve in a certain direction. He observed that a ball with topspin dropped faster than a ball without spin. Inversely, hitting the ball in a certain way can make it spin backward causing it to have a lift in the air and cover a little bit more distance than usual.

But that’s not all there is to it. There was another person to perfectly describe this phenomenon. In the year 1742, a British mathematician named Benjamin Robins also described this natural phenomenon.

He was also a military engineer and ballistic researcher. During his research, he discovered and explained the curved path of spinning musket balls shot out from musket guns.

But Heinrich was the first one to rigorously investigate this phenomenon and explain in detail. And thus he was credited for the discovery of this effect and which was named after him.

History of Magnus Effect

How Does Magnus Effect Work in Airsoft Hop Up?

Now that we now about airsoft hop up system and Magnus Effect, How does it work on hop up?

When a BB is shot using an airsoft hop up system, the BB’s shot out while rotating backward. When the BB is traveling in a straight path, it’s actually moving through the air. Which means it’s moving against the airflow.

Even if the air is not moving towards the BB pallet, since the BB is shooting through the air it will cause the same effect. While moving through the air, the trajectory of the BB deviates and it’s lifted upwards for some reason creating a curved path.

But why is that?

What’s the mystery behind this sudden turn of events??

Honestly, you can stop reading here if you like.

Coz there is some serious science mambo jumbo from here on out.

I’ve tried to explain it as easily as possible with much detail but if you don’t like the science of physics at all then please do avoid the rest of this article.

Although I advise not to if you want to really understand the science behind airsoft hop up and the range & accuracy!

But if you’re short on time and still want to learn the truth behind airsoft hop up and Magnus Effect the then you should definitely watch the 3-minute video at the end of this article.

People usually use 2 different ways to explain Magnus Effect –

  1. Newton’s 3rd Law of Motion
  2. Bernoulli’s Principle

Before explaining either one, please examine the visual representation of a non-spinning airsoft BB shooting through the air –

Non Spinning BB
Non Spinning BB

A.      Newton’s 3rd Law of Motion

Newton’s 3d Law of Motion states that “For every action, there is an equal and opposite reaction”

So how actually this Law of Motion causes Magnus Effect?

Let’s explain it a bit shall we?

Yes, we shall!

Remember when I talked about a BB moving through the air and flowing towards BB are the same thing?

At least they are the same when it comes to fluid dynamics and relativity.

When a back spinning BB is moving through the air, it’s actually dragging some of the air around to its back due to friction. And since the BB is spinning, the air around it tends to spin as well which causes the air to flow on the BB’s back a bit downward. It creates an equal and opposite force from the air molecules as well.

Now you can say that if the BB can make the air flow backward then it’ll also make it flow forward as well.

Yes, that’s quite true!

In fact, since the BB is spinning, it should make the air around spin with it or in other words, make the air flow in all the directions. So the BB should receive reaction force from every side making the net force on the BB zero.

If the reaction force applied to the BB from every direction is the same, then the BB won’t move from any of those forces making the total sum of the force null.

But In a scenario where airsoft hop up is used, BB is not only spinning but also moving through the air. We can think of this as air moving towards the BB. Since the BB is spinning backward, it’s just making the airflow faster by dragging it behind.

That’s why a reaction force received from the back will be stronger than any other direction. This causes the BB to deviate from its path and lift due to the upward reaction force caused by the airflow that was moved by the BB spin.

But Newton’s 3rd Law of motion isn’t the only one that explains Magnus Effect. There is another theory in existence which seems to conflict with the Law of Motion.

See the image below for a better understanding,

Spinning BB 3rd Law of motion

B.      Bernoulli’s Principle

Bernoulli’s Principle states that “Within a horizontal flow of fluid (gas or liquid), an increase of speed occurs when the pressure is decreased and decrease of speed occurs when the pressure in fluid increase”

But what does that have to do with Magnus Effect or airsoft range?

It has a lot to do with airsoft BB trajectory actually.

In contrast with our first explanation where the BB is lifted from the counter force of the air molecule, according to Bernoulli’s Principle – the BB is lifted due to difference of air pressure.

So how the pressure difference is created?

Remember our first explanation above?

The back spinning BB drags the air flowing towards it and make the flow even faster. So the air that touches the upper part of the BB flows faster.

On the other hand, airflow slows down on the lower part of the BB.

As the air is flown to back by the back spinning BB’s upper part, it also regulates air flow from back to front on the lower part. So on the lower part, it creates a blockade for the air flow coming from the front. So the air flow on the bottom slows down a little.

Now we get two different speed on different sides of the BB. One where the air flow has become faster and one where the airflow is slower.

According to Bernoulli’s Principle, low pressure creates increased speed and high pressure creates decreased speed. Inversely, high speed can also cause the pressure to decrease while Low speed can increase it.

Now we are almost at the climax of our explanation!

It’s time to come down with a proper conclusion.

According to Bernoulli’s equation, in a steady flow of fluid, the total energy remains the same between any two points. So when there is a difference in pressure, fluid tends to move from high pressure to the low-pressure area to balance the energy just like Thanos!

If you want an easier explanation then I should say, nature doesn’t like empty spaces. So when pressure decreases in one place and starts to get emptier, high-pressure area moves in and fills the low-pressure area until they reach an equilibrium i.e. same pressure.

When high-pressure air from the lower part of the BB flow towards the upper part of BB where the air pressure is low that’s when the lift happen. This is how BB deviates from a straight path according to Bernoulli’s principle.

You’ll surely understand when you see the image below,

Magnus Effect According to Bernoulli’s Principle

If that wasn’t enough then we have a 3-minute video for you explaining Magnus Effect.

Magnus Effect Explanation

So which one do you think is accurate? Newton’s 3rd Law of Motion or Bernoulli’s Principle?

Which explanation was legit?

Write a comment below to let us know about your thoughts.

And finally, Thanks for reading this through.

New To Airsoft? Read This Articles =>

Airsoft: Beginners Guide

Do you play Airsoft?

Airsoft Tips To Become a Pro

Pin It on Pinterest

Share This