The Multi-Target Missile System is a TitanOrdnance that appears in Titanfalland Titanfall 2. The Multi-Target Missile System enables you to engage multiple targets at once. Hold down the Ordnance Ability control and sweep your view over your targets to paint them. Then release to fire the missiles at the painted targets.
This locks on one rocket at a time then fires all locked rockets at a time. This holds a max of 12 missiles at a time, but missiles can be fired individually. This is a good tactic to keep an enemy's shields down while reloading.
Note: You can "paint" several targets in this manner, OR you can keep the crosshairs on the same target to lock several missiles on that target. In this respect, the Multi-Target Missile System is a better version of the Slaved Warheads.
Hold to automatically lock on to many targets at once.
The MTMS returns in Titanfall 2, though with some changes. At launch, it was only available in the campaign as a part of the Expedition loadout. In the campaign, these missiles can target infantry as well as Titans.
The MTMS was not added to multiplayer until the Monarch's Reign update, which added the Monarch Titan. The missiles are available as a potential Tier 3 upgrade of the Upgrade Core, serving to replace the Rocket Salvo that is otherwise default for Monarch.