Not too long ago, we talked about the bucking which is a component found in all airsoft guns. Now let's talk about the next component that it interacts with: the barrel.
Airsoft guns have two barrels. Yes two, technically. There is the outer barrel which is the exterior part that you do see. This serves no function in firing the gun per se but it is integral to mimicking the look of the firearm that the airsoft gun is trying to replicate. It houses a second barrel, the inner barrel. The inner barrel is what the actual BB travels through when it is fired, and with the exception of some oddball designs out there, it will be for a 6mm plastic BB. The barrel system will consist of the barrel itself, the rubber hop up bucking, a hop up nub, and the hop up chamber.
The barrel has a direct effect on accuracy, range, and velocity but it must work in synergy with the bucking and other components inside the gun. If your gearbox is not performing properly you will not have the air pressure to achieve range and velocity. If your bucking is worn out or torn, the same results will occur and you might have feeding issues on top of that.
The barrel is a pretty straight forward component. The inner diameter will have a measurement of 6.05mm or more and typically be made of brass, steel, or aluminum. Brass is what you will find the majority of the time. The barrel will have a window cut into it one one end, and this is the end where the hopup chamber presses the nub into the bucking which protrudes into that window. This produces that bump from the rubber that will make contact with the BB as it is fired, thus providing backspin and giving you the hopup effect. Read more about buckings here.
So what makes a barrel more accurate and a worthy upgrade? You'll hear the term "tight bore barrel" in airsoft. This is where the barrel has a smaller inner diameter, typically 6.03mm or 6.01mm or even 6.00mm. Typically, a BB is measured at 5.95mm +/- 0.1mm. A tighter barrel means the BB won't be moving around as much and should deliver a more consistent grouping. The tighter constriction also means the air pressure is increased ever so slightly and you will likely get a boost in velocity out of the same ammo. This can be verified by a chronograph, a device that we use in airsoft to measure an airsoft gun's performance, more specifically the velocity and energy a gun is capable of.
There are other concepts and barrels that exist besides the tight bore, but this is the most prevalent and proven concept for airsoft barrel types. So what diameter is right for you? The tighter you go, you will almost always get the most FPS, but it comes at the cost of reliability. Sometimes the barrels are so tight that the slightest dust and debris, or a less than perfect BB can jam your gun up badly. If you play indoors primarily, your environment is probably more sterile and you can get away with a 6.01mm or 6.00mm barrel. If you play outdoors, I would recommend a 6.03mm. A 6.01mm will work too, but be careful about getting dirt in the barrel and with any of the barrels you upgrade to, clean your gun regularly.
Next thing to consider in a barrel is the material it is made of, or more specifically how smooth it is. Brass is the most popular for a factory barrel, and also work just as well for an upgrade. On cheaper guns the barrel equipped will be a brass or aluminum barrel. These barrels work fine but they have a very rough finish inside and though this is not ideal, it does not impede the function of the gun. Nicer barrels will have a nice finish and that could potentially reduce friction from the BB travelling down the barrel and improve velocity just a tiny bit. It is hard to say by how much without actually polishing the barrel, so let's just say that a nice smooth inner barrel is added value and makes us warm and fuzzy inside. If you are upgrading, the material is a personal preference and having used all kinds, brass, steel, and aluminum have all worked fine for me and I don't exclusively run anything based strictly on material, only based on the smoothness.
The ones we stock at Fox are from a few brands, but our accuracy package is based around Madbull products. Madbull offers aluminum 6.03mm barrels called the Black Python which are our favorite and work best for everyone's needs. We also have their aluminum 6.01mm and Steel Bull series 6.03mm barrels which also work well.
A lot of people ask us what is the best first upgrade to do? Is it to upgrade the velocity by changing the spring or the barrel? If your gun has a quick change style gearbox, upgrading the spring is great for achieving that raw power. If you're trying to tune for accuracy and efficiency, the tight bore barrel route is the way to go. You will get a small bump in FPS which for some people is all you need since you have field rules to follow. A big jump in FPS might put you in a different category at your local field. Also note that upgrading the barrel does not put any strain on the gearbox or draw more juice from the battery the way a harder spring or different motor might. Barrel upgrades do not require disassembly of the gearbox so you can get this upgrade installed with relative ease for many types of guns. Some guns require disassembly of the body which can be more work in itself.
If you have more questions about upgrades reach out to us!