Difference between buying a low cost airsoft m4 rifle and a decent airsoft gun

Is there a difference between buying a $40 m4 rifle and a $150 m4 rifle? Why should I buy a more expensive model gun?  What sorts of issues will I have with the cheaper model m4 rifle or other cheaper model gun?

So, you are thinking of buying an airsoft rifle for yourself or someone you know.  However, you know next to nothing about these guns and cannot seem to see the difference between the cheaper gun and the more expensive ones.

The biggest difference you will see is quality!

A $40 AEG or Auto Electric Gun is the $40 gun will be almost all plastic and is really just a cheap toy kind of like you would buy at the dollar store only this costs $40.
The internals, or motor of the gun will have plastic gears, which will inevitably strip over time.  How long is anyone's guess.  Could be in a week, or a few months.  As long as you understand that this gun just will not last and probably break after a few uses but might be what you are willing to spend for a first gun, then this is the gun for you.

The barrel and stock of the gun often break from being dropped or just man-handled.  This is due to being cheap plastic and poorly made.

The fps or the ability of the motor to shoot the bb out at a certain speed also will vary with a cheaper model gun. Most guns in the $40 range will have less than 200 fps (usually 120-220 fps) which is not really strong enough to play in a real skirmish.  You will be outgunned and the people with the $150 guns will be able to shoot you at 150 feet, while you can only shoot about 50 feet with any effectiveness. 

The battery that is shipped with these guns are really next to useless.  Throw them out and buy a decent battery.  The chargers are the same, next to useless.  Buy a decent rc type battery charger or smart charger and get a good ($20-$30 range) battery.  Most skirmishers buy more than one battery so that their gun will last in an all day skirmish.

Parts.  There really are no parts for these cheap guns, it is better to just buy a new one. 

Now we will talk about the entry level guns.  Those $40 guns are not really even entry level as they will not allow you to play with any decent chance of success.

The entry level guns in airsoft generally start around the $150 - $200 range.  These guns are often made in China and have strong ABS plastic or metal.  A good gun in this range is Jing Gong.  For a chinese airsoft gun, they make a decent entry level choice.  They often have metal parts and actually come with stock high fps. 

Chinese made mid-range products often have slight wobbles in the barrel and stock and where they lack is the robustness of the motor and gears.  This causes the gears to wear out over time, although they usually last a good 2-3 years with proper care.  Often they have metal parts and metal gears, which last much longer than your plastic gears.  They can also take more of a beating if you acidentally drop them although stocks often break if the gun is dropped.  The stock fps of these chinese airsoft guns are usually about 300 - 380 fps.  This is good for playing at a real skirmish as the fps limits are generally under 400-450 fps.

There are a few entry level airsoft m4 rifles and other guns from some manufacturers from Taiwan, which are generally better made than those from China., although Chinese made guns have come a very long way in the last few years for durability and quality.  Because the Chinese guns are close to the more expensive guns, you can usually modify or upgrade them with more robust internals if you desire.  For example, if you had a decent chinese gun, and used it for 3 years or so, then your motor went, you could keep the body of the gun, and get new internals to upgrade your gun, thereby getting more use out of it over time.
Because of the many different types of airsoft m4 rifles and other airsoft guns, most people just buy another new gun and keep collecting more and more.

The top level guns, such as a TM, are made in Japan or Taiwan and suprisingly have a lower stock fps than the chinese guns.  However, their motors and gears are top notch and can last many years and are easily upgradeable.  You are looking at spending $400-$900 for this type of gun.

A great analogy for buying an airsoft m4 rifle or other airsoft gun is much like car buying.  You do get what you pay for, and you need to decide if you would rather buy a used $500 car vs a decent $5000 car or buying a new 2010 model car.  I would highly suggest not buying the $40 AEG airsoft gun, and sticking with the $150 gun for an entry gun, if you are pretty sure airsoft is a hobby you would like to get into.