User blog:Cheezitman/FOR HALO 2 (part 6)

Glitch: House Of Flying Energy Swords
This bug/trick may be used in any level (and on any mode, Campaign or Multiplayer). To perform it, you must have both a plasma sword and any other firing weapon (the rocket launcher works the best).

Equip the non-sword weapon and place the reticule over a valid target (i.e., an enemy) such that the reticule turns red. Press Y to change weapons and the instant before the sword's reticule replaces the non-sword reticule, pull the R trigger.

If timed correctly, the player will lunge forwards as if the sword locked-on the target to deliver the lunging sword strike. Note that this glitch is effective regardless of the distance between the player doing the glitch and the target.