This is a comprehensive guide on how to adjust the hop up of an airsoft sniper rifle, along with some tips for tuning. This article assumes that you already have some knowledge about how hop-up works as it explains in detail the adjustments and operation of this mechanism.
What Is Hop Up?
Hop up (also known as airsoft adjustment) is a mechanism that applies backspin to the BB, making its trajectory above 100 feet flatter so that it travels farther. It makes the projectile more stable in flight and therefore helps it retain its energy over longer distances.
The major components involved in this process are the rubber bucking, nub, and barrel.
Before we get into the adjustments to create this backspin, let’s review these components.
The Rubber Bucking
Rubber deforms under air pressure created by the combustion of gunpowder in a round. Since there is no airtight seal with BB in an airsoft chamber (unlike a real firearm), a rubber bucking is used to compensate for this deformation in the barrel. It creates an airtight seal between BB and the inner wall of the barrel so that backspin can be applied.
The Nub
The nub is located inside the hop up bucking. When it comes into contact with BB, it applies backspin to it. It is adjusted so that the downward force exerted on BB by this nub creates a certain amount of backspin on BB, and hence a flatter trajectory over 100 feet.
The Barrel
Backspin is applied on BB by either pushing or pulling it during its travel through the barrel. A good airsoft gun barrel is smooth and does not cause friction with BB as it travels through the barrel.
How To Adjust Hop Up On Airsoft Sniper?
Adjusting hop-up on a sniper rifle is different from adjusting it on an AEG (advanced electric gun) or GBB (gas blowback) due to the power of airsoft sniper rifles.
Not all airsoft guns are capable of adjusting their hop-up, so you should check your owner’s manual for more details. If it is adjustable, here are some tips on how to adjust hop up on sniper rifle:
General Tips
When adjusting these components during or after skirmishes, make sure that the rifle is cool and clear of any debris or BBs. Doing so may damage your rifle if it is too hot.
Bucking Adjustment
Adjusting bucking requires the use of a barrel spacer and some tape (preferably electrical). To adjust the bucking, follow these steps:
1) Lay out the electrical tape on a flat surface in an oval shape
2) Place the barrel spacer (spring-loaded metal donut) on top of the tape and secure it with a piece of tape. Make sure that the place where the metal donut rests is not narrower than the inner diameter of your bucking. If such is the case, add another layer of electrical tape to make up for this excess space.
2) Wrap electrical tape around the metal donut and secure it with a piece of tape as shown in the picture below:
3) Now place your bucking on top of the nub end (opposite to where you applied electrical tape). Make sure that the bottom half of your bucking is at the same level or lower than the metal donut. In other words, there should be some space between your bucking and the metal donut.
4) Secure rubber bucking with a couple of pieces of tape to ensure that it doesn’t move while you’re adjusting airsoft hop up.
5) Turn your hop-up unit from minimum to maximum repeatedly to adjust bucking.
Nub Adjustment
During skirmishes, some of the backspin can be applied by the barrel to BB if your hop up bucking is tight enough. However, there are times when you have to do it manually as well. When this happens, you should keep in mind that adjusting nub requires more precision than adjusting bucking. That’s because the nub’s job is to add a backspin on BB whereas bucking simply holds BB in place while it travels through the barrel.
To adjust nub, follow these steps:
1) Lay out the electrical tape on a flat surface in an oval shape. If your airsoft gun bucking has one side with deeper grooves, place that side facing up to form a deeper groove. This is easier than trying to wrap it around a smaller groove.
2) Place your nub on top of the oval-shaped electrical tape and secure it with a piece of tape. Make sure that there is no excess space between your bucking and the metal donut.
3) Now wrap electrical tape around the metal donut, over your airsoft nub, and secure it with a piece of tape.
4) Secure your rubber airsoft bucking with a couple of pieces of tape to ensure that it doesn’t move while you’re adjusting airsoft hop up.
5) Turn your hop-up unit from minimum to maximum repeatedly to adjust nub.
Barrel Adjustment
The barrel length is important to consider because it sets the distance necessary for BB to acquire enough speed for a stable flight motion, i.e. 50 feet and further. Basically, the longer the barrel, the more air a BB has to travel through. Thicker barrel walls and slower rifling twist rate slow down the speed of BB as it travels through the barrel.
In general, heavy BB usually requires a longer barrel. Because heavier BB doesn’t travel as fast as lighter ones, it takes more distance to receive enough speed for a stable flight.
Airsoft Sniper Hop Up Adjustment: Spring Tension
Adjusting the hop-up spring tension changes how hard BB is pushed by the nub. This in turn affects the amount of backspin applied to BB, and hence the flight trajectory over 100 feet.
Rifles that have a high muzzle velocity require a higher spring tension to make up for the loss in backspin due to air drag.
As a general rule, you don’t want your hop-up spring to be weak enough that BBs need more than 1 second to hit the target when fired from 100 feet away. For example, if it takes 1.5 seconds before BB hits target at 100 ft, you should probably change your spring or use heavier bb, because it will most likely not hit the target from 100 feet distance.
Airsoft Sniper Hop Up Adjustment: V-Frog Adhesion and Nub Merge
V-frog adhesion is the amount of grip that your V-frog has on BB when fired. A nub merger refers to how the hop up bucking and nub form one continuous surface around the barrel chamber. There are three types of hop up unit designs.
To achieve a good airsoft hop up to BB adhesion, the nub should be pushed hard into the V-frog when you apply a backspin on it by twisting the hop-up wheel. The compressed V-frog surface thus forms a better grip with BB as it travels through the barrel.
The combined nub-bucking surface forms a smooth, continuous surface on the metal donut. If your airsoft hop up unit has an open gap between bucking and nub, BB will easily exit from the barrel chamber if there is not enough backspin to hold it in place.
Airsoft sniper with poor adhesion (left) and excellent adhesion (right).
V-Frog Surface Pattern
The surface pattern on the bottom of the airsoft V-frog determines how strong your BB will stick to it. The more aggressive the texture, the stronger the adhesion. Use sandpaper or other abrasive material to roughen up the surface of your V-frog.
Conclusion
Adjusting airsoft hop up gives you better control over the BB flight pattern. You should readjust your airsoft hop up every time you change bb weight and/or barrel length. Before trying to adjust it yourself, identify what type of unit you have so that you can go through the steps accordingly. If you are still having difficulties, it is advisable that you get a professional to help you adjust the airsoft hop up unit.
Strong adhesion between V-frog and BB will result in longer-range shots with higher accuracy, because your BB may not be affected by environmental air pressure or wind during flight.