What is a Hop-up?
Don't worry about sounding like a "noob". This is a very common question for those starting out in airsoft as well as the veterans. The hop-up unit is an essential part in every airsoft gun. Because BB's are very light, once they leave the barrel, the effects of the world around them (wind, rain, gravity etc.) causes them to lose velocity rather quickly.
In order to negate this effect, the hop-up unit gives your airsoft gun a clever little backspin to keep it travelling for longer.
As you can see by the diagram above (courtesy of Orange Tip Tactical), the hop-up assembly has a number of parts. Hop-ups come in a range of shapes and sizes, but effectively they all have the same function in mind.
The bucking and nub is what gives the BB the much needed backspin to keep it travelling through the air for longer. Typically they will have a dial of some kind to either weaken or strengthen the effect of the hop-up. This is located in that little groove of the barrel with a hole. The nub pushes through creating a little contact with the BB through the bucking as it flies through the barrel, striking the bucking and creating backspin.
How do I adjust Hop-up?
There are so many different types of hop-up unit depending on the manufacturer, weapon style and speed of shooting. Some will have a simple dial to adjust them, while others may have more complicated and intricate methods like levers. Most of the low budget AEG's will have a standard hop-up system, which the user can adjust via a wheel you turn to increase or decrease the pressure on the bucking against the BB.
On the other hand, there are better and more precise hop-up units out there if you feel the need to upgrade. Often they will have a closer thread diameter, meaning it takes more turns to adjust, enabling you to have better control over the level of hop-up you want.
The only way to setup the hop-up is at a range or large and safe open space. Ideally you need to fire a few shots and look how the BB travels. If it falls to the ground quickly, then you need more pressure from the bucking and therefore need to tighten the hop-up.
If you notice the BB curls upwards, then it could be that there is too much pressure from the nub on the bucking on the BB, causing it to lift.
The best setting is to try to get the adjustments just right that the BB fires straight with a slight upwards arc near the end of its path. This will enable you to achieve maximum range.
Hop-up Bucking
Most experienced players know that the bucking and nub set up is far more important when it comes to improving accuracy and range. A wrongly set hop-up results in reduced range and accuracy.
The bucking (also know as hop-up rubber) is inserted on the end of the barrel over the small slit in the tube. The purpose is to hold the hop-up unit together with the barrel, create a tighter air seal with the "lips" of the bucking being against the nozzle and providing backspin (hop-up) through contact with the BB as it passes through the barrel.
There are various types of bucking that is hard or soft, which can affect their performance as well as overall durability.
A softer bucking will grip the BB better ensuring a strong backspin, but has reduced durability, and a harder bucking will provide less backspin, but will be more durable.
It is also worth noting that cheap quality buckings can stiffen and have less effect in cold weather.
Hop-up Nub
The nub is a small, cylindrical tube of rubber that acts as a barrier between the hop-up arm/screw and the bucking. The nub allows for softer compression between hard plastic/metal and the rubber bucking to avoid damage as the BB passes through by giving a level of flexibility, increasing the lifespan of the bucking. Many experienced airsofters will change their nubs to be certain shapes, like a curve, to provide a better hop-up that flat nubs cannot always achieve. Usually when you purchase a bucking, the nub comes with it as a set, but make sure to check first, as this is not always the case.
Degrees of Hop-up
Hop-up units come in many variations with different strengths, thicknesses, density etc. Much the same as a pencil eraser, car tyre or shopping trolley/cart wheel.
Deciding which type of hop-up system you want is your choice, whether you want a harder or softer bucking to give better friction or more reliability. Generally the harder buckings provide more reliability and durability, at the cost of less friction.
The "degree" of the bucking is related to the Shore durometer.
20 Degree is similar to a rubber band 40 Degree is similar to a pencil eraser 60 Degree is similar to a car tyre 70 Degree is similar to a rubber shoe sole 100 Degree is similar to a shopping trolley wheel
The three main degrees of the bucking are as follows
Low degree (soft = 50 - 60)
Medium degree (firm = 60 - 70)
Hard degree (hard = 75+)
One final aspect to consider is the temperature when you play. The thickness will determine whether or not the bucking will harden when cold. A soft bucking warms up faster than a hard bucking. But, it is better to research the bucking as some will have compounds to react differently to certain weather climates/temperatures.
Just make sure that before you buy, the bucking is the right fit for your weapon as they are not really all a standard size.
Note: This was rewritten after a request from a Redditor for following the same format.
This is great and quite easy to follow. I never knew how complex the hop-up system was until now.
Thank you! 😊