Which airsoft BB weight you should use is a common question. If you’re a new player in the sport, it can be difficult to know how the weight of the BB can affect the performance of your airsoft gun.
So, in today’s blog, we’re going to go through how changing the weight of the BB will change your airsoft gun’s performance, and which weight of BB is best suited for your airsoft gun.
How does BB weight affect performance?
There’s a really simple way to visualise how the weight of a BB might affect the performance of your airsoft gun. In this hypothetical situation, replace the BB and airsoft gun, with a tennis ball and your arm.
You can throw a tennis ball a certain distance, let’s say 30 meters. There’s just enough mass in the ball to be stable during flight and to be less effected by air resistance.
However, now replace the ball with a ping pong ball. No matter how hard you throw the ball, it’s unlikely to achieve more than 10m. The ball is simply too light and is easily affected by wind and air resistance, no matter how hard you can throw.
Now, lets replace the ball with a cannon ball. You might consider yourself a strong person, but the world record for shotput is 23m. However, the ball is now not hindered in the slightest by wind or air-resistance and is arguably more accurate than the above two.
This should give you some insight into how different weight BBs might affect your airsoft gun’s performance. However, this is all entirely relative. What happens to the above relationships if you were to have a much stronger, or weaker arm? With super human strength, you could throw a cannon ball much farther than 30m and be much more accurate with it (it’s barely affected by wind and air resistance).
So now, it comes down to which is the right BB weight to use for the power of your airsoft gun.
BB Weight per Joule
First of all, we will be talking about airsoft gun’s power in Joules, not FPS. We have written extensively about why joules is superior to fps for airsoft gun measurement. However, put simply, the FPS of an airsoft gun will change with BB weight and so we would struggle to offer a BB weight for the FPS if it keeps changing.
As a simple rule of thumb. Take Joule rating of your weapon and divide it by 5 to get a decent indicator of which weight BB to use. However, it’s relatively common for players to vary the weight of the BBs they used by a few fractions of a gram depending on preference.
1 Joule / 5 = 0.2g BB (Most AEGs and Pistols)
Most AEGs and Pistols fire within the 1 joule to 1.15 joule range. Most players using airsoft weapons at this power level will play with BBs somewhere between 0.2g and 0.23g. However, some players do use a higher weight BB. As mentioned earlier, this can affect range, but does improved the stability of the shot. Many players will shoot with up to 0.28g BBs on AEGs and Pistols.
DMRs and other single shot long range rifles fire around 1.6 joules of energy and players often use BBs in the range of 0.3g to 0.36g. Since the rifle has a higher power, it’s able to throw the heavier BBs further with greater accuracy. The BB is less effected by air resistance, and has the velocity behind it to carry it’s momentum longer.
This is the higher limit of airsoft rifles (in the UK at least). 2.5 joules is close to our legal limits. Many airsofters will use a BB weighted between 0.4g and 0.5g to get the most out of their rifles here. Similar to above, it means that the BB carries momentum much further, since it’s less effected by air resistance and wind.