The poor man's sniper rifle, the Shock Rifle is extremely accurate and far reaching. Three hits usually take a bot down. Too bad it doesn't come with a magnifying scope.
Alt-Fire produces some type of plasma balls which are mostly useless, unless you can perfect the art of detonating them with the primary fire. Once you master this, the plasma balls are an effective way to shoot around corners, or clear out infantry.
When used against vehicles or people, the shock rifle hit can physically move or upturn them. This can be especially helpul on maps with ledges, in preventing people from getting to a flag.