I have been playing Airsoft for about 2 years now and am addicted to this sport. And yes, it IS considered a sport! Not enough people recognize it as one, so I want to keep it going, you know. I love Airsoft because it is competitive, there is a lot of strategy involved, you get to use realistic weapons, and its good exercise!
Thanks Alot and I hope you enjoy this Instructable!

***DISCLAIMER***
In some countries, states, or other localities Airsoft might be restricted. Or, some laws might be put on these weapons, such as in Germany, you are limited to the amount of energy the gun puts out. Please, do obey all of your laws in your country. In most government's eye's, Airsoft is a dangerous sport that could be taken in the wrong way. So don't repaint your flash hiders, go shooting your neighbors, or play across your street because local authorities will call the police and if you are under 18, than your weapon will be confiscated and you might be given a fine. We need to be mature with our weapons, so we can really spread the good word on how fun and addicting this sport really is.

Step 1: Backround

Okay. Not alot of people know what Airsoft is in the first place (Mostly Parents), so I will give you a detailed description of the sport.

Airsoft is a combat based sport, similar to paintball, involving air-guns and shooting small plastic spheres (aka BB's) at each other. The game is alot more realistic than paintball, and can be argued, but I think it hurts less. Its more of a stinging pain than a bruising pain.

As said in the intro, there are many precautions you should take when playing airsoft. Here are a few:

Always keep your gun on saftey until you are ready to fire.
Never keep your gun open in public
Be sure after you are done using your gun, to clear the firing chamber by removing the mag and firing a few rounds in Semi Automatic.
Never use your gun in public
Always wear eye protection.
Never remove the orange tip on your gun.
Always keep your finger off the trigger unless you are ready to shoot.
Never fire on people who aren't playing with you.
Always treat your Airsoft gun like a real firearm.
Never look down the barell of any gun.
Always use high quality BB's!!!!!!!
Never disassemble your gun unless you are a trained mechanic and know a 110% on how airsoft guns work!
Make sure you follow these rules.

Step 2: Location, Location, Location

Ask yourself this: Where will you and your friends be playing Airsoft? In your back yard, on a public Airsoft feild, or in the middle of the woods? Make sure wherever you play you have permission to play there. Another thing: What type of Airsoft? CQB or Feild? If you play on your own property, then renevation might be an idea. What worked for me and my friend, if you are in the woods, use a rake or an ATV with a plow to clear away all small brush and leaves. This will prevent new plants from growing there, and your feild will look very nice. If you have the resources, you might want to build bunkers or tree houses for cover. In the middle, have a rally point. Somewhere where there is a flag or a main land mark that you can 'capture'. I will explain this more later. Trenches would also be a good idea. If you are up North, than the dirt will be hard so bring a Pick-Ax, a Shovel, and a friend. Well, a backhoe would be the best, but not many people have that lying around in their garage. :P Aside from that, you should be set on knowing your feild.

Step 3: Your Weapons

The Guns: These Airsoft guns come in many different types:

The most common type of Airsoft Weapon is the AEG (Automatic Electric Gun). (Pic 1). This is preferably full metal, but these things really pack a punch. How do they work? An electric motor that is fitted inside the handle grip spins some gears inside the gearbox, which then intern pulls back a piston, which compresses a spring. The last gear connected to the piston is only toothed half-way, so that when it completes the revlotion the piston rockets forward, thrusting air into a narrow hole, and the only thing blocking the hole is a small, high-grade .20 or higher Gram BB. These AEG's usually have hi-cap magazines that hold around 350 rounds. These magazines have 'trap doors' located on the top of the magazine, which you would open and pour until full. Then, you wind a wheel at the bottom of your mag, and stop winding when you hear a satisfying 'click'. AEG's can come in pretty much every style of assault rifle/ SMG that are real firearms. Plus, on some of the higher end models, the parts are actually compadiable with real guns. For example, RIS rails, Optics, Lasers, Flashlights, Bipods, Iron Sights, Verticle Foregrips, and more. All AEG's are powered by a battery, which can be located either in the foregrip, upper reciever, or stock of your gun. These are usually Assault rifles, but SMGs are also AEGs, so you are going from CQB (Close Quarters Combat) up to Mid range with these guns. Spec Ops and Assault stuff. Can cost from $180 to $1150+. The FPS (Feet Per Second) ranges from 250-450. Some examples: Ak-47, M4-A1, MK5 (MP5), M16, G3, and MK16 (SCAR).

Next up, Spring powered rifles (Pic 2). No, this isn't your $12 Walmart See-Thru crap. These are mostly full metal, execept for grips or buttplates. These are composed of agonized rubber. Spring powered rifles are usually Long Range Rifles, or Sniper Rifles, and Shotguns. These are ALOT simpler to understand than AEGs. Basically, you pull back a bolt or grip which then inside the gun pulls back a piston which houses a really strong spring. When you push the bolt or grip forward, the piston catches on the trigger sear, and the bolt locks down into position. You pull the trigger, and the compressed air sends that BB cruising accurately through the air. Most of these rifles have an optics mounts, and getting a scope would be a good idea, since the gun can shoot farther than you can easily see through the iron sights. Can cost from $99 to $1000+ FPS range: [Shotgun] 280-350; [Sniper Rifle] 400-550. Some shotgun examples: M500, M3, and M58. Some Sniper examples are: L96, M1324, BAR-10, and R700.

Not as popular as AEGs or Spring powered rifles, is Gas Powered Rifles (Pic 3). These are very rare and range in popularity from Sniper rifles, Assault rifles, and Shotguns. These have the most complex design in my opinion. You have to load green gas into the magazine, which restricts the capacity of the magazine. On a sniper rifle, pulling back on the bolt only chambers the next round, instead of pulling back a spring. When you pull the trigger, it sends a burst of pre-compressed air from the magazine into the barrel and shoots your round. The down side of using gas is that you have to carry green gas or propane with you every where you go, and if you are a sniper, you have to pack lite. Plus, these guns only work the best in warm weathered situations, because the gas contracts with the absence of heat, so you would drastically loose FPS. Cost? More expensive ranging from $350-$1200+. FPS: [Sniper] 480-560 [Assault Rifle] 400-480 [Shotgun] 300-380. Some Sniper examples are R700, L96, and some custom models. Assault Rifles: MK16 (SCAR). Shotguns: SG9000.

The most popular type of sidearm: GBB (Gas Blow Back) Pistols (Pic 4). These use the same technique as Gas powered rifles, only it is the most sefficient and popular use in a pistol where space is restricted due to size. Still there are two options: CO2 Canisters or Green Gas. I personally belive CO2 is alot more effective because you never have to buy green gas (which is hard to find in everywhere but California..?), and propane stinks, isn't good for your gun, and is flammable. You can get CO2 anywhere. The same firing mechanism with Gas powered rifles, only you just have to pull back the slide before you squeeze off your first round. Costs: $75-$999 . FPS: 300-380. Some examples: Bretta M9, 1911, M93R, M702 and Colt.

The Least Popular type of side arm: the EBB (Electric Blow Back) pistols (Pic 5). These are like mini-AEGs that fit inside a pistol. Very unreliable, low FPS, and inexpensive. They are good for CQB incase your side arm fails or something. They have high rates of fire and are usually fully automatic. Costs: $60-$150. FPS: 250-330. Examples: M93, M92, G18c, and G17.

Hop-Up (Pic 6)
This is important. Very important. All high quality airsoft guns have this. It's like basically putting rifling on an airsoft gun. On the gun, lets say its an M4, you would pull back the charging handle to reveal a small wheel. Making miniscule rotations, turning this wheel clock-wise will push a small rubber peice to come down from the top of the inner barrel. It should be so little you can't even see it, but it will do its job. It basically adds backspin to the BB while its flying through the air, so it flies straighter and doesn't drop as early. Very Important for sniping.

Okay! This should cover your knoledge on Weapons!

Step 4: Game Types/ Techniques

Game types:

Assault
The most popular game type of Airsoft is Assault or Deathmatch. Can be played as CQB or Field. Simple. Two even teams of players start on either sides of the feild. If you get shot, you either go back to a 'respawn' or 'die'. When you 'respawn', you have to go to a specific 'respawn point'. These are usually going to be located at the point where you first started the game. These games can have a time limit, and usually do if you respawn. Each time a player respawns, he goes back and marks a paper at his base. When times up, the team with the least marks wins. If it goes by 'deaths', if you get shot, you have to permenately go back to your base. last team alive, wins!

FFA (Free For All)
Fast paced, usually CQB, but occasionally you can play it out in the woods, where it would be ManHunt. Players spread out so they can't see each other. When a round is fired or sound grenade goes off, then the players have to go seak out and 'kill' each other. If you get shot, you are out for that round. There is no time limit. The best comparison I can give you to this is if you play Call of Duty: Modern Warfare 2. This is basically like Search and Destroy, without the bombs. Teams are custom, usually by player name. Last one alive wins!

CTF (Capture The Flag)
I can relate to this. Me and my friend play in these huge woods on his property and we went on a walk one time and found two huge "kegs" of Helium, used for inflating balloons. He invented a gametype that was the exact same thing as CTF, only subsitute the F for Keg. CTK. Wow. Anyway, its a two or more teamed game that does have a time limit. If you get shot, you have to respawn back at your base. In some variants, if you are carrying a flag (or Keg :P) than you can only fire your side arm. The player that has the most captures in a set period of time, wins!

Riot Attack
Players are armed with a home made Riot Sheild. (Can be made out of thick plexyglass. I might make an Instructable on it later.) If possible, it would be optimal to do this in a urban place. ONLY on your property, or property you have permission to use. This has basically no rules. Two teams. Military (in the Riot Sheilds) and Militia.The militia is heavily armed, while the Military is lightly armed. The side that wins is the side that holds out the longest, either by surrendering, or running out of ammo.

Demolition or Hot Potato
This is fun. Get a airsoft grenade and rig it for a long timer (5-10 minutes). This is FFA with some twist. One lucky person gets the Grenade, and has to find other players and stealthily hide it by other players without them knowing. Once the grenade goes off, the person who planted it wins. Players are very lightly armed. Pistols with only one mag. Ghillie Suits would be useful here.

Cover Wars
Again, I owe this idea to my friend. This is strictly for CQB. Basically 1 versus 1. There is heavy cover all around the arena. You have to play a game of cat and mouse here, so to say. To start, both players croutch behind cover. When a gun is shot to start the round, the players both pop up, or usually one does. First one to Hit the other player wins.

Tie Breaker
Another one of my friends ideas. Short and Sweet. Two players have C02 revolvers with only one shell in each one. The players start back to back and have to take three long strides then whip around and draw their gun and shoot their opponent. First shot looses!

Quick Draw
Similar to Tie Breaker, only this one has a dirty twist to it. Players stand only five feet apart from each other and when someone not playing says to go, they empty out all six shells on the apponent. Obviously the one who gets hit first surrenders, because 480 fps from five feet hurts like hell!

Duck Hunting
This one is exactly like it sounds. Two players, one person has only one round in their weapon. The other is unarmed and is standing perpendicular to the armed one, 20 feet away. The unarmed player has to jog for 20 feet across the feild or to a land mark, while the armed player has to fire one round and hit him. If the 'runner' passes the checkmarks, he wins. If he gets hit, the armed player wins.

Duck Sniping
This is duck hunting on steroids. The armed player has a 480+ FPS sniper rifle and is 100 feet away from the 'runner'. The runner has to run 50 feet without getting hit. Same rules apply for both.

Night Opps
This is the most difficult. Same as assault, really, only in the dark with tracer units mounted to the guns, night vision optics, and RIS mounted flashlights. Pretty fun!

These are all ideas really. I am sure you can come up with alot more than I can, though! :P

Step 5: Apparel/Player Positions

In Airsoft, you can get almost every type of armor or battle unifor that Armed forces use today. There are many types of Apparel. Here are a list of a few and what positions you would be to use them:

Tactical Vests
Assault Class. Carry lots of Ammo, grenades, and a Pistol. Obviously would be carrying an Assault rifle.

Light Vest
First Recon, or a scout. Carries less ammo, packs light, so he can move faster. Would be armed with a Machine pistol or an SMG.

Plate Carrier/ Hydration
Heavy Gunner. Caries TONS of ammo, alot of protection, explosives, and some water. Would be armed with a LMG.

Ghille Suit
Sniper, or marksman. Caries low amounts of ammunition, but is the stealthiest one of all. This suit blends in 110% with your surroundings, so you know you won't be found. This person would weild a DMR, which is a AEG sniper rifle, or a regular gas or spring Sniper Rifle.

Step 6: Upgrades

Are you look at your Airsoft Gun and are bored, dissapointed or feeling Inferior? It might be time for an upgrade. Just like with cars, there are many performance upgrades, and many cosmetic upgrades. The most common upgrades are on AEGs. Occasionally, the other parts are for replacement, but sometimes upgrading from stock value. Here is a list of some:

External:
RIS (Rail Interface System)
Flashlights
Laser
Outer Barell
Barell converter
Flash hider
Iron Sights
Full Metal body
Verticle Foregrips
Motor grips
Stocks
Scopes/Optics
Bipods
Grenade Launchers
PEQ box
Front End Conversion Kits

Internals:
Full metal 8mm Gearbox Upgrade
Spring
Tappet plate
Heat treated steel gears
Full Metal Hop-Up
High grade Piston
High grade Piston Head
Tight Bore Internal Barrel
9.6+ Volt Battery with 2000+ MAh
LiPo Battery (CAREFUL! VERY VOLATILE)
Motor
Low resistance Wiring
MOSFET

Others
Smart Charger
FPS/RPM Chrono

Step 7: Online Buyer Guide!

The Internet is the most common place to buy Airsoft Guns. ***Disclaimer*** In America, you must be over the age of 18 to order any type of Airsoft purchase, but I am unsure about the rest of the world. Here are some trusted websites:

http://www.shortyusa.com

http://www.airsoftgi.com

http://www.evike.com

http://www.airsoftmegastore.com

http://www.airsplat.com this is just a resource, but I personally wouldn't trust airsplat.com.

The rest, however have wonderful user ease and are very informative on their site. Me, being on the east coast of America find that Shorty Usa is a wonderful resource because it is so close. Here are some tips to look for when buying any Airsoft equipment.

-Make sure that the websites compare prices with others, or has a "Price Match".
-Look for how organized the website is. This will help you to find your products.
-Look for websites that let users rate products. From here, select the best selling or highest user rating.
-When you buy any gun, be sure to get a Full Metal version, or one with at least a Full Metal Gearbox.
-Depending on your game type, different styles of guns would be a consideration. For example: for CQB: Shotguns, SMGs and Pistols. For Feild: DMR, sniper rifles, Marksman Rifles, and Assault Rifles.
-Look for Clarity in the Pictures. Some websites like Airsplat, have really fuzzy small pictures and you almost can't even see what your going to buy!
-Some good websites let you use PayPall when you check out. This might be of ease to you.
-Make sure that the website that your are using updates its self daily. With the best, its hourly!

Step 8: Friends!

Airsoft is one of those sports that you can never enjoy alone. You enjoy it best when your with your best buds, all on the same team, working together! Form a club on www.facebook.com, for example. Here all of your friends and local in your town can get together and play airsoft. Plus, you can organize place to play, and even meet some new friends!

Step 9: Outro

Okay. That is all of my knoledge of Airsoft. I do hope this helped you and I want to spread the good word on the sport. I must warn you though: IT IS ADDICTING!!!! Almost as addicting as Pistachios, according to NCIS. :P Anyways, thanks for your time and bring a good name to Airsoft across the world! Thank you Instructables!