Curiously I asked my parents if I could stop by to play the next day. I arrived to find what looked like a bunch Marines preparing for a war. The clear plastic guns I have previously seen were no where in sight. Instead full metal exact replicas of real guns were all there was. In the 'battleground', I played in everything from miles of woods to a middle eastern style town.
The guns shoot with three main power sources. What most of us play with, spring, requires you to manually reset the piston every shot through spring, like nerf gun. On the field, the most common way is electrically, known as an AEG (automatic electric gun). This runs off the same principle as spring, except it uses an high torque motor to perform the task. The coolest way I have seen would have to be with pressurized gas. With these guns, pressurized CO2 or propane is used to propel the BB and also cycle the bolt of the gun, giving it a realistic recoil, or jerk whenever it fires. All of these can be used interchangeably, and it is more a matter if preference.
Similar to paintball, a player yells "Hit!" when shot by another players. But the difference is that there is no splatter. Instead the guns shoot 6mm plastic BBs much more accurately and at a farther range. The whole game revolves around an honor system, which definitely has its down falls, but I personally enjoy.
Ever since then I have been hooked. The adrenaline you get when you look down the sights and pull the trigger is incredible. People always ask why I would want to play a game where it hurts when you get hit. The reason why is because of the fear of pain is what really get your heart pumping, and it makes it feel a whole lot better when you don't get hit.
During the day I was surprised to find that airsoft was a way of life for some people. Airsoft is like a real life video game. There is everything from multi-day operations, to even helicopter gunners.
All in all, I was lucky to stumble upon such a cool activity, and if you has chance to play, I would highly recommend it.