The Railgun.

The Railgun is a firearm weapon that can be accessed by pressing 7 or R on the keyboard or by switching weapons manually, (scrolling). The Railgun is a popular weapons, and function sort of like a sniper rifle for Quake Live. It takes over 3 seconds to recharge after being fired, delaying your next shot, however being such a strong weapon, it can be used in combination with the lightning gun as a 'finisher' when the opponent is close to dying. This prevents any escape as it hits hard and fast. It's highly accurate and fires a depleted uraniam slug in a straight line. Each slug does 80 damage to the opponent regardless of where it hits. Being a hitscan weapon, there is no splash damage.

This is the only weapon you will start with in an 'Insta' game.

NOTE: The Railgun is perhaps Quake Live's most effective harassment weapon. If you have low HP and armor, try to predict where your opponent(s) are likely to appear and position yourself so as to snipe at them with the Railgun. After scoring a hit, run away and repeat. 2-3 hits will even out the playing field no matter how large of a stack advantage your opponent has. The rocket launcher can perform in this role as well, but unlike the Railgun, it restricts your ability to quickly escape (due to its shorter effective range).