Launch super-heated slugs at individual foes, or hurl the entire weapon and ignite groups of enemies in a flash inferno.
The Javlok is a staff-like primary weapon that fires slow moving fireballs that deal Heat damage. Its unique Alternate Fire allows the weapon itself to be thrown at enemies, dealing area-of-effect damage which is boosted by the remaining ammunition in the magazine.
The Javlok's alternate fire throws the weapon itself at the target, inflicting 150 physical damage to the impaled target and 300 area-of-effect Heat damage to all enemies within the impact radius.
If thrown without a full charge, the detonation area is indicated by a glowing aura around the weapon before detonating after a short fuse.
The Javlok will remain at the location where it was thrown for ~20 seconds after landing, automatically teleporting to the player after said duration or until the player manually picks the Javlok back up for use again.
Throwing the Javlok will consume all of the ammo in the magazine, but only when exploding. Throwing the weapon at close range and picking it up before it explodes will not consume ammo, nor will it explode.
Picking up the weapon after exploding will require a reload.
The Javlok's alt-fire has a max throwing range of ~50m (though it will be displayed as 47m due to the ~3m the player moves forward when throwing the weapon).
The arc Javlok will take when thrown is affected by both the angle of the throw as well as how much the throw was charged.
Although the alt-fire AoE inflicts Heat damage, it has a guaranteed knockback effect, staggering all affected enemies for a short time.
While the Javlok's secondary fire can be charged while wall-latching or mounting a zipline, the weapon itself will not be thrown until the player dismounts from the wall or zipline, upon which the Javlok will immediately launch.
This also applies to sliding and can result in unintentional, often lethal damage if the user is aiming too low.
As of Update 19.11.5, primary-fire projectiles explode on impact dealing AoE damage against enemies within 1.6m radius (unsure if affected by Firestorm but testing didn't show a perceivable difference). Oddly the blast radius against the players appears to be 3.8m (unaffected by Firestorm), it's unknown whether this difference is a bug or intended.
The ability to equip the Adhesive Blast mod was removed in Update 21.3.1, likely due to it having no effect and no benefits if it did.
Primary fire projectiles are affected by punch through, although it only affects map geometry, similar to the Grattler.
The Javlok pairs well with Ember as her Accelerant ability multiplies the amount of Heat damage taken by an affected enemy, and the Javlok deals exclusively Heat damage if left unmodded.
Both the primary and alt-fires of the Javlok can be controlled by Ivara'sNavigator.
The Javlok's primary fire mode has an Alarming noise level, but the alt-fire itself is considered Silent on launch, therefore will not break Ivara's Prowl.
Will hit all enemies currently affected by Vauban's Vortex.
Alt-fire will pierce and hit the head of an enemy taking station in a Rampart even without punch through.
Alt-fire is unaffected by mods that require you to aim to gain benefits (i.e. Argon Scope, Bladed Rounds) on account of the weapon being in flight. It's advised to mod accordingly if you plan on using the alt-fire extensively.
The Javlok Capacitor, which drops from Grineer Prosecutors, can be easily farmed for on Ceres missions where multiple Prosecutors are nearly guaranteed to spawn.
The AoE from Javlok's alt-fire does not seem to be affected by Firestorm.
Sometimes the Javlok will not be able to be equipped after picking up for a period of time, forcing the user to switch weapons.
In the Simulacrum, throwing the Javlok, then changing your primary weapon before it returns will disable your primary weapon until you exit the Simulacrum.
Having punch through on the Javlok and using the alt-fire will cause it do a self-harming explosion for yourself that has no graphical indicator, but won't physically "explode" and damage enemies until it's reached a sufficient stopping point in flight. You also don't want to have -accuracy, as it will seemingly shift the AoE radius in such a weird way that it will damage you if thrown too close.
The AoE from throwing the weapon does not seem to damage the orbs from Sapping Ospreys. (Tested. The AoE does damage to already deployed orbs, but not to arming ones. Only a direct hit from the thrown Javlok can damage arming ones.)
If you alt-fire on a Nullifier Crewman's bubble, you will lodge the Javlok into it, and if you manage to take the bubble down completely, your Javlok will disappear with the bubble. If you kill the Nullifier, you will be forced to wait until your Javlok returns. However you can still pick up Javlok while it's still on the bubble.
While Hall of Mirrors is active and having thrown the Javlok with alt-fire, picking it up will result in the thrown weapon disappearing but not actually returning to Mirage's possession. The weapon will still reset back into inventory after 20 seconds.