How to Adjust Your Hop-Up Unit

Back to Blog
How to Adjust Your Hop-Up Unit
Category: Airsoft Basics


When it comes to airsoft basics, nothing is quite as basic as being able to adjust your hop-up unit. However, with that said, the amount of times the question “why are my BBs shooting upwards/downwards?” comes up in the safe zone, it’s a basic that very few people actually know about when first starting airsoft.

Essentially, the hop-up unit is found within AEG Airsoft Guns (Automatic Electric Gun) and is responsible for applying backspin to each BB as it leaves an airsoft gun. This is due to BBs being extremely light, meaning the majority of the velocity applied to each BB is lost after leaving the barrel. The backspin applied is a means to counteract this, essentially making a BB act like a glider once it has left the barrel.

Hop-up units are generally found in different places dependant on the model of your chosen airsoft gun; however, you will find similar models will have similar hop-up locations. With that said though, we’d be here for hours if we explored the hop-up locations of all Electric Airsoft Rifles (AEG) ever brought to the market, so we’ll be sticking with the two most popular variants on the market – the M4 and M16.


While some hop-ups can be extremely difficult to get to, airsoft variants of the M4 and M16 are fairly straightforward to work with. As previously mentioned, there are a vast number of different hop-up units cycling through the airsoft industry, but the M4 and M16 tend to use the same hop-up unit, leaving the adjustment wheel in the same position – behind the bolt-in dust cover.

To adjust the hop-up, you simply move the wheel clockwise to increase the hop-up or counter-clockwise to decrease it. Increasing the hop-up will place more backspin on a BB, leading the trajectory to rise, while decreasing the hop-up will place less backspin, leading to a fall in trajectory. Pretty simple stuff!

But how do you go about achieving the perfect hop-up setup? Simply put, trial and error. First off, you’re going to need to find yourself an open and safe environment in which you can test your rifle – ideally you’ll do this before playing a game as you will notice a slight level of creep between uses. Secondly, you’re going to want to let a number of single fire shots off, adjusting the hop-up as you go to gain the best trajectory. In an ideal world, a BB should fly straight, achieving a slight upwards ark towards the end.

Bear in mind that you’re never going to get pinpoint accuracy from an airsoft gun though, so do not sit there for hours trying to achieve the perfect line. This is due to airsoft guns not having a rifled barrel-like their real-world counterparts. With this in mind, simply realise that you’re not going to achieve unrivalled accuracy from each shot!

If you would like more information about Airsoft Guns or BB Guns and Hop-Up units please see Just BB Guns.

Share this post

Back to Blog