How do you throw a knife?

In order to throw a knife, you must reach level seven in LIVE. Now, equip the Throwing Knife Equipment to one of your classes. Now, once you are in a LIVE match, press RB and you will throw your knife.

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First be aware that you cannot throw the normal combat knife, and in the story (single-player campaign mode) the knife that you can throw – naturally called the “Throwing Knife” is only available to your character in the "Endgame" mission, when MacTavish uses it to kill General Shepherd.

In the multi-player modes access to the Throwing Knife is unlocked as part of your regularly selectable kit at Level 7, after which point it appears in the Equipment Menu at the start of each level... The Throwing Knife deals damage that is equal to or slightly better than the standard Combat Knife; but bear in mind that (A) it is always a one-hit-kill weapon and (B) it's use will cancel “Last Stand” or “Final Stand” as it immediately kills the player, just like the Knife does.

When you select the Throwing Knife as your ranged kit at the start of a mission you will only receive ONE (1) Throwing Knife. That is OK though because it is re-usable, which means that if you kill an enemy with it, you can then go to the body and retrieve it – and if one of your mates throws THEIR Throwing Kinife you can also retrieve that (to the total of one Throwing Knife) no matter who actually threw the Knife and as long as the Throwing Knife is flagged among your starting kit you will be able to take and use it.

If the target that you killed with your knife falls off the edge of a cliff, or you miss and the knife is lost to the environment, or you are not able to find where it ended up, there is a chance that you can replace it using the Scavenger Ability. Bear in mind though that certain obvious restrictions do apply to the use of this weapon...

If you fancy yourself the consummate special operator you should make every effort to learn how to lead moving targets, and how to judge distances, to take into account the fact that your thrown knife will “drop” the farther from the target you are when you throw it, which makes it necessary to aim slightly above the target just like when you are making long-distance sniper shots.

You have to put it as your equipment. While in game, press the RB button

When you have throwing knives selected as your lethal hold down RB to aim and release RB to throw