Chronographs are handy tools that help fine-tune the performance and abilities of an airsoft gun. Not only do they ensure you can safely shoot at airsoft sites and stick to the regulations, but they are also useful when testing the effects of gun modifications.
Find out more about what chronographs measure and when to use them.
What is Chrono in Airsoft?
Airsoft chronographs (or simply chronos, as they’re often referred) are useful bits of kit that measure the muzzle velocity of your gun, indicating how powerful (and, therefore, potentially dangerous) it is.
Testing muzzle velocity is the basic function of any chronograph, although various designs also offer other measurement readouts. You’ll typically find that they measure:
- - Feet per second (FPS)
- - Rate of fire (ROF)
- - Rounds per second or minute (RPS/RPM)
- - Power in joules (when the weight of the BBs is programmed in)
Airsoft chronos are usually handheld devices, which makes them convenient to bring along to your skirmishes. Many of these devices come with LCD or OLED displays and are powered by either USB cables or batteries. Some higher-end chronos can also record your results, which makes comparing data over time easier.
Understanding Chrono Measurements
It’s all well and good seeing the numbers on a screen, but what do they actually refer to, and why does it matter?
What is FPS?
FPS is the speed at which a BB is travelling at any given point in the trajectory. As with all guns, this decreases the further the bullet travels from the initial source of power (the gun). Chronos measure the maximum FPS, which means the speed of the pellet as it leaves the chamber, along with the rate of fire, often measured in RPS (rounds per second).
What are Joules?
Whilst FPS is purely the speed your BB is going, joules are specifically a measurement of the energy the BB has and can be worked out by using the FPS and the weight of the BB. A heavier BB travelling at the same speed as a lighter BB will have more power.
If you thought that wasn’t confusing enough, if you take into account joule creep, most airsoft guns will not maintain the same power with a 0.2g BB as they will with a 0.3g or 0.43g BB, but that’s a whole other subject!
Why Use an Airsoft Chronograph?
Chronos help you understand the power and output your gun is capable of. This is important for several reasons.
1. Abiding By UK Laws
There are a number of laws around airsoft gun usage that every player needs to be aware of. Power limits are strictly enforced, and wielding an airsoft weapon that exceeds the legal limits can get you in serious trouble with the law.
- - Full auto airsoft guns: muzzle velocity can’t exceed 1.3 joules
- - Semi auto airsoft guns: muzzle velocity can’t exceed 2.5 joules
Chronographs allow you to ensure your gun fires within this legal range.
2. Respecting Skirmish Site Rules
Aside from national law, there may also be particular regulations to follow when it comes to each skirmish site. Many have their own specific rules to keep players safe, so it pays to have a chronograph on hand to show you’re shooting within the accepted range (skirmish sites will also have their own chronos for you to use if you don’t have one).
The typical limit is around 350 FPS, but it's also a good idea to check with the site when visiting. Sites will ban you from playing if you are not willing to chrono your gun.
Sites will often also implement a minimum engagement distance, meaning that guns of a certain velocity can only engage with enemies a set distance away. This helps prevent any injuries or serious wounds from high-powered BBs.
3. Understanding Your Gun’s Performance
Another key reason you might want to chrono your airsoft gun is that it gives you a deeper understanding of its performance. A chronograph will provide data on how fast the bullet travels, allowing you to better judge different battlefield situations for improved consistency and accuracy.
If you’re making changes and additions to your gun, seeing the difference in readings will better illustrate whether what you’ve changed has had an effect or whether other adjustments are needed.
How to Chrono an Airsoft Gun
Using chronographs is relatively simple. Start by setting up your testing area to ensure you have enough space to shoot safely, with a stop to catch the BBs if necessary.
- 1. Set up your chronograph in front of your gun’s muzzle, lining up the chrono’s shooting gate and the barrel.
- 2. Fire a few test shots to make sure everything is set up properly.
- 3. Now, record the velocity of the BBs as they pass through the chronograph. Make a few shots to get an average velocity.
- 4. If the value is too high, make the necessary adjustments to your gun.
- 5. Test with the chrono again to ensure you are within the appropriate range.
Make sure you shoot straight or your readings will not be accurate. The weight of your BBs will also obviously change your energy output.
If your gun is being tested at a skirmish site, you will likely be guided through this process by the staff. Do not try to cheat your way through by lying about the weight of your pellets. This will only compromise the safety of other players and risk a ban.
The Best Airsoft Chronographs
If you’re often tinkering with your guns and honing their performance, it is worth having your own chronograph so you can test your changes.
The ‘best’ chronograph generally comes down to your budget and which guns you own. There are some really nice devices on the market now that offer incredibly consistent readings. However, there are also some more budget options that are perfect for new players.
A few popular and reliable options include:
There are plenty of options for an array of budgets. However, we recommend staying away from the cheapest of the cheap as these can offer less consistent readings. Whichever chrono you choose, make sure that your guns can fit the opening and have no issues firing into the chamber.