Ranged weapon-switching

From Halopedia, the Halo wiki

Ranged Weapon Switching is a skill that is used to grab weapons from afar at the cost of at least one grenade (or explosive device). This is a trick that is easy to learn but hard to master.

How to

First, throw the grenade just behind a weapon of choice such that the weapon is between you and the grenade. When the it explodes, the weapon will go flying over towards you (if you aimed right). Jump just as the weapon gets past you and hold (X). If done correctly, you should have the weapon in your grasp. If you already have that weapon in your disposal, you will just get the ammo.

Weapons to use

This is very useful if you are in dire need of another weapon to suit the situation, or if you need ammo. Possibly the most famous of these switches is the sniper-sword on lockout. As the match starts, the player runs to the sword spawn, grabbing plasma grenades on the way. After picking up the sword, the player runs forward and looks up at a wire crossing the map. The player uses the grenade to propel the sniper across the map into their arms. All this can be done in a few seconds at the start of the map.