The M57 Rocket Launcher can lock-on to air vehicles, even when hipfired. Unlike in previous games, aircraft like Banshees and Phaetons can never escape a missile from a locked-on M57 Rocket Launcher, regardless of the pilot's skill.
The missile can only be stopped by scenery objects, such as tall walls or buildings.
As with the previous M41 SPNKr Rocket Launcher, never aim directly at an enemy player on foot with a rocket launcher. The small, fleet tendencies of an enemy soldier makes it next to impossible to score a direct hit, especially with the addition of Spartan abilities, making rockets easier to avoid. Instead, aim for their feet, and perhaps a little bit ahead of where they are. Players near the rocket's splash radius can be killed, and if they aren't killed, keep a secondary weapon (preferably a precision one) to finish them off with a quick headshot.
It is effective against Hunters and Promethean Knights, capable of killing at least one even before having expended two clips of the weapon, provided the player has another heavy weapon as a backup.
Unlike other UNSC weapons in Halo 5: Guardians, the Rocket Launcher can kill a player character in the campaign and make them unrevivable if the rocket directly hits them.
If this is done to a human player in co-op, he/she will have to wait 60 seconds before respawning.
Warzone features two additional variants:
Ad Victoriam: an improved M57 that fires three laser-guided missiles in a V-shaped formation and feature a proximity airburst fuse, as well as faster reloading time but with a trade-off of an 18.4% slower missile speed. As the missiles can be guided using Smart Link, the Ad Victoriam is recommended for dealing with campers and/or enemies in hard-to-reach places, as well as dealing with vehicles or bosses.
High Five: an advanced M57 that fires five Hydra mini-missiles capable of seeking out both land and air targets; at least two of the missiles must hit to kill a Spartan. It also has the longest red reticle range of any weapon, capable of target detection from up to 762 m (2,500 ft) away with its 5× zoom. The High Five is most effective as an anti-infantry weapon, but is otherwise still proficient against vehicles and bosses. It also has the slowest missile speed of the three Rocket Launchers, with 27.7% less speed than the standard model, which makes it less effective at longer ranges.