It looks like there’s a bit of a gap in info regarding this hobby here.
Paintball—well, the tactical version—is really designed as a team sport; you can't just go Rambo on everyone and expect to win. The replicas are basically 1:1 scale copies of real gear, and they use magazines that function just like the real thing—meaning you actually have to swap mags mid-fight. Generally speaking, the crowd involved is pretty decent too; people call their hits, which tells you a lot about the type of folks getting into this...
As for the cost of gear... look, for maybe $500, you can pick up a pretty solid replica and enough basic kit to keep you going for a few years. Bigger events usually happen every month or two. For ammo, you're looking at roughly $33 2500 BBs per batch.
Most of the action happens out in the woods, though lately we've been doing more CQB/urban stuff. Between the tactical options and the gear being used—which is often actual military surplus aside from the guns—you get a massive range of playstyles and training setups. In some countries, they even bring in helicopters, armored vehicles, and paratrooper drops via military sponsorship. Honestly, a lot of people who are fed up with standard Paintball—at least the kind played in those tiny 100x100 meter patches where you just burn through paintballs for no reason—tend to migrate over to this...
The "field" is never smaller than a square kilometer or so; you need that kind of space to actually pull off any tactics. Most of the skirmishes simulate commando or diversionary raids since we don't have artillery support or much manpower, and we're always on a clock—so that's how we fight. Some games have respawns, some don't, and others run medic rules. The scenarios themselves are pretty complex—way more involved than something like Capture the Flag—and they require you to actually know how to navigate the woods, judge distances, and all that jazz...
We use topographic maps with elevations and routes marked out to make sure everything gets finished properly.
Right now, there are several teams operating across the States... our main hub is
www.airsoft-america.com where you can hit the forums to ask about anything. You can usually arrange to rent a rifle for a game, and that's also where new events get posted. It's easy to jump into technical gear discussions or just reach out to someone more experienced if you're lost.
The rifles themselves work by using a battery to tension a spring, which then pushes air to fire the BB forward. You can find almost any modern iconic weapon available... with a standard battery, you can usually dump about 2000 BBs before you run dry, which is plenty.
Pistols are gas-powered and have a slide that cycles just like the real thing—they behave exactly like it, too (you'll need to rack the slide, etc.).
If anyone is seriously interested, I could put together a gear presentation, but I'd also suggest just logging onto the forum, checking the A-H sections, and renting a rifle for a match before you go out and drop a ton of cash on your own setup.
I can already see the forum trolls coming for me, so let me just clear a couple of things up:
1. We aren't "militarists"—as in, we aren't cheering for wars in Iraq or Afghanistan or whatever. Anyone who plays this and sees it as a realistic combat simulation knows firsthand how easily you get taken out. If more people spent their time doing this, there'd probably be fewer actual conflicts!
2. The BBs we use are completely biodegradable within six months, so they don't mess up the environment (unlike all the trash and junk people leave behind in the woods).
EDIT: Forgot one thing... the most important piece of equipment in the whole kit is your eye protection. You can see it in that photo above where the guy is holding the M4... you never, ever take those goggles off during a fight.