Guys, if a weapon is hitscan, it travels instantaneously. If I remember correctly, the sniper takes two frames to travel across Sandtrap. Is it realistic that you could move away in one frame? No. But it isn't a hitscan, which is the important distinction.
And the spartan laser travels further than most maps in one frame. Check it on the campaign missions, with larger maps. Hitscan is instantaneous; it finds out where it will hit, be it an enemy, a wall, or the skybox, as the trigger pulls. Halo 3 weapons don't do that, they collide when they collide, not when the trigger is pulled.