*Note: This FAQ is to describe how airsoft BB's can affect FPS,
Joules and the trajectory of your shot. It is also recommended that
you have a Calculator on hand*
Lets start off with some of the acronyms and terms you will see
during this FAQ.
FPS: Stands for Feet per Second, classifies the
power of any gun.
CQB: Close Quarters Battle also referred to as
CQC or Close Quarters Combat.
Joules: Also a way to calculate the power of an
air-soft gun. This is more accurate than FPS is.
AEG: Automatic Electric Gun.
How to gauge the power of your airsoft gun:
The easiest way to gauge the power of
your airsoft rifle or pistol is by checking the FPS. Our website
tells you what the FPS is on each model of airsoft gun. These are
averages, not exact. Many forces (mainly gravity and friction) act
against the BB and will cause the FPS to drop considerably as soon as
it leaves the barrel of the gun. FPS is how many consumers,
manufacturers and the worlds governments gauge and regulate air-soft
guns. Because of it’s easy to understand nature this system has
been widely accepted world wide and is used by many.
A high grade air soft gun will usually have a higher FPS than a
lower quality clone but this doesn't always apply.
FPS also increases and decreases with what weight of BB you use.
Examples are as follow:
380 FPS with .12 Gram BB’s
350 FPS with .20 Gram BB’s
FPS with .23 Gram BB’s
320 FPS with .25 Gram BB’s
FPS with .28 Gram BB’s
300 FPS with .30 Gram BB’s
As soon as the BB leaves the barrel, because there is no more
force acting against the BB and it will begin decrease in speed
dramatically. Its also a good idea that after 50 feet to subtract 100
to 150 FPS from your equation. FPS can also be affected by the
environment including wind, air, and barometric pressure that can
We recommend only using .20 to .25 gram BB’s in your
standard AEG (Automatic Electric Gun) to increase, accuracy,
performance and lengthen the life of your gun. .28 and .30 gram are
meant for upgraded AEG’s and Sniper Rifle style of airsoft gun.
You will see that .12 holds the fastest speed and .30 has the
slowest. Keep in mind that even though one is traveling faster than
the other they will both travel the same line, on average to the same
spot. However, the lighter BB will get there faster and the heavier
BB will have more energy stored in it making it go slightly further.
The easiest way to measure the FPS of your airsoft gun is to use a
Chronograph to gauge its speed. A Chronograph uses light to track the
speed of the BB leaving the barrel of the gun from one point to
Keep in mind that many airsoft guns need seasoning or breaking
into shoot at the FPS that the manufacturer or the merchant has set
forth. It is a good idea to put at least 300 rounds through the gun
the get to its true potential.
We will talk more about the exact difference of weights in BB’s
later in this FAQ.
Joules is another way to calculate the
power of your gun. A Joule is a measurement of energy and is stored
in every BB. Different weights of BB's can also hold a certain amount
of energy even though they are made of plastic or biodegradable
ingredients and are the same size as its lighter or heavier
You will normally not see Joules as a form of measuring power on
many website because it is much more complex and uses a mathematical
equation to find out the amount stored in each BB. Unlike FPS, Joules
will stay at a constant in conditions with harsh winds and days with
clear sky and no breeze.
To find out your Joules, you will first need to turn your Feet per
Second into Meter Per Second using the mathematical equation.
M=F x 0.3048
Then turn your Grams into Kilograms using this equation.
Kg=.001 x G
The Equation that is used now for you to get the amount of Joules
in each shot is this.
E=½ x M x V^2
M= mass in kilograms
velocity in meters per second
We will use 270 FPS and .20g BB in this example equation:
275 x .3048 = 83.82 Meters per Second
.001 x .20 = .0002
½ x .0002 x 83.82^2 = 0.702579
So in a .20 gram BB going at 275 FPS carries 0.702579 Joules of
energy in each shot.
By measuring your airsoft guns power in Joules you can get a
better feel for how accurate and powerful your gun is. An airsoft gun
that shoots at 380 FPS with 3J hits much harder than one that shoots
380 FPS with 1J, so please take safety into account. Use a trial by
fire method, would you want to be shot by your own gun? If you
wouldn't like it, I doubt your friends or other players would like it
Now that I have confused you enough let me sum up what just
happened. The FPS effect’s your Joules which are affected by
the weight of your BB. So the heavier the BB the more energy in the
BB giving it more force so it can travel longer and straighter (and
it will hurt more!)
How a BB can affect your shot:
It is simple rule of thumb to never use .12 BB’s in AEG and
High Power Spring air-soft guns. Because of there low quality they
can break inside the gun damaging your air-soft gun or even
destroying it if there was a jam. .12 gram airsoft BB's are also not
seamless and may contain a lot of burrs (defects). The BB's you
usually get at your local sporting goods store are .12 gram unless
they specify heavy weight and the amount of Grams. Even though the
price for .12 gram BB’s are tempting it’s not worth
ruining your gun to save a few bucks.
When we say we recommend that you use .20 to .25 grams it really
is for the better. This is one of the reasons we do not carry .12
gram BB’s. We only want to carry quality product in our
warehouse for our customers to use.
You may be thinking, "If it lowers my FPS, what’s so
good about a heavier BB?"
There are several different reasons why a heavier BB is better. If
you were to compare a .12 to a .20 BB you would notice on the .12 BB
a seam in the center of that circles the entire BB and a burr on the
top where the plastic is injected into the mold to form the round.
The .20 (or higher) will not have this, there will be no seams or a
burr on the top that will make the BB inaccurate or cause your gun to
jam. The seam and burr creates weak points on the BB making it more
liable to shatter on impact or in the gun. These also throw off the
trajectory and balance of each BB making them non-uniform and highly
disliked by many players.
With .28 or higher you are looking at a very heavy weight BB. We
only recommend that you use these BB’s in upgraded or higher
end models that use all metal construction and tight bore barrels.
.28 and higher may not also feed in to some guns so you need to be
careful. The last thing you want is a jam that could possibly ruin
With the difference in the weight of each BB you will also get
different amounts of resistance to wind and barometric pressure. The
lighter the BB the more likely the wind will grab it throwing it off
course making the shots inaccurate. The speed of the BB does not
affect the accuracy, just how fast it will get from the barrel to the
target. Heavier BB’s will be able to have lest resistance with
wind and will mainly travel straighter and farther than a lighter BB.
Remember if you do have a jam, do not continue pulling the
trigger. You could destroy the gears and pistons by stripping them
which means you are looking at expensive repairs or buying a new
air-soft gun because this is not covered by any manufacturer
warranty. It is best to stop shooting, remove the magazine and
battery and take the unjamming rod and push the BB out and then feed
one BB in at a time to make sure everything is working correctly
before going out to play.
How all of these will affect one another:
Now that you know and understand the how FPS and Joules work
together as well as how a BB and your environment can affect your
shot. All these things need work in conjunction with one another. FPS
tells you how fast the BB is going, Joules tell you how much energy
is stored in it and how uniform each shot is, while the brand and
weight of BB affects both of these.