Alternate Fire modes (or alt-fire modes) are unique methods of attack featured on many weapons in Borderlands 3.
Atlas weapons shoot a tracking round as a secondary fire mode, which deducts a single round from the user's reserves. Any enemies tagged with tracking rounds will glow red, and all regular shots will target a tracked enemy for a duration that is dependent on the nature of the tracking round fired. Smart-bullets will travel slower and leave a noticeable red trail while homing on targets. An audio cue will denote when an Atlas weapon has locked onto a target, and small red arrows will appear on the crosshairs.
There are three standard types of tracking rounds:
- Tracker Darts: A small number of darts are shot in a shotgun-like burst. Darts can tag one or more enemies and have a short recharge time. Overall the most reliable and effective tracking system.
- Tracker Puck: Fires a slow-moving magnetic puck that sticks to the enemy it's shot at. Upon the target's death, it will drop off and has a chance to seek out a new target within a small radius. The puck's tagging effect lasts for eighteen seconds. Designed for tracking large, single targets and generally the least effective form of tracking.
- Tracker Grenade: A grenade-like charge that is shot in an arc. Bounces up on impact with terrain and explodes into hundreds of darts that will track all enemies within the burst radius. The grenade can prematurely explode on directly impacting an enemy. The grenade's tagging effect lasts for twelve seconds. The best tracking system for tagging many enemies at once.
Dahl weapons switch between two different firing modes. This will change the behavior of the gun as well as the sight's zoom.
Of the following, two are available per weapon:
- Semi-Auto: Single shots; usually combined with a stronger zoom.
- Damage for all applicable Dahl weapon types will be increased, except for pistols.
- Burst Fire: A burst of 3-5 bullets. Also usually comes with the stronger zoom magnification.
- Full-Auto: Holding down the trigger will fire continuously; usually has the weaker zoom
Maliwan weapons can switch between two different Elemental damage types.
Torgue weapons can switch between their regular explosive projectiles and sticky explosives. Once stuck, these sticky bombs will rapidly explode in sequence of impact when the weapon is reloaded, the mode is switched or the character switches to another weapon. Each successive stuck projectile will do more damage depending on how many rounds detonated before it, for possibly extraordinary amounts of single-target damage.
Vladof weapons have various underbarrel attachments that offer a different way of dealing damage. All secondary weapons will use the same ammo type as the weapon they are attached to, making them more efficient in many cases. Vladof underbarrel attachments include:
- Taser: Tasers fire in a slight arc and will continuously deal damage to both enemies directly hit and enemies around the taser itself, which means even missed tasers can still do damage if the user can keep enemies in the taser's vicinity. Uses ammunition from the character's ammo reserve rather than the current magazine, and regenerates itself after a few seconds.
- Zip Rockets: Fires tiny rockets in a straight line. It has its own magazine which will regenerate after a short time.
- Second Barrel: A secondary barrel below the regular one. The barrels rotate after every shot, increasing the fire rate of the weapon by 25%.
- Grenade Launcher: Does not draw from the current magazine and has a maximum capacity of 2-4 grenades that can be launched at one time. Regenerates one grenade at a time.
- Secondary Chain Gun Barrel: Unique to Bezoomies, a second chain gun barrel located underneath the main barrel. By default, only the upper one is active. When toggled, they will rotate by 90°, activating them both for 15% faster fire rate. Ammo consumption and recoil will increase with the fire rate as well.
Assault Rifles/Sniper Rifles:
- Bipod: Switching modes deploys a bipod that drastically improves Handling and Accuracy, but reduces movement and aim speed.
- Shotgun: Possesses variable projectile counts and pellet damage statistics, and like the grenade launcher attachment, the weapon regenerates one shotgun round at a time separate from the main magazine but will draw each round from the user's current ammo reserves. Each shot of the shotgun will take one bullet.
- Rockets: Similar to the Assault Rifle's Grenade Launcher, this attachment grants additional explosive projectiles. The amount of Rockets can vary.
- Triple Barrels: Unique to Bratchnies, two additional barrels in a triangular configuration are underneath the main barrel. Upon toggling the fire mode, the barrels rotate, providing a 35% increase in Fire rate. This comes at an accuracy penalty and more pronounced recoil.
- Micro-Rockets: This alters the method of projectile delivery, rather than being an alternate weapon attached and draws from the current magazine of the weapon. Each round fires two micro-missiles which deal 75% the weapon's stated damage at a high fire rate.
- Big-Boy Rocket: The damage dealt by this single rocket is at least double, and sometimes triple that of the normal rocket fired. Regenerates its round relatively slowly, but does draw from reserve ammo pool and not the current magazine.
- Mortar: Designed to assault enemies behind cover. Regenerates its round relatively slowly, but does draw from reserve ammo pool and not the current magazine.
Only one Eridian weapon, the Eridian Fabricator, exists. This mode consumes 250 Eridium and fires 4 items which can be one of the following:
- A legendary weapon.
- A unique weapon with red flavor text.
These weapons can spawn with anointments. However, it will not produce DLC weapons.
- Unique and legendary weapons can differ from their manufacturer's regular Alternative Fire Mode in various ways. Examples include:
- Many, such as the Cloud Kill, Krakatoa, Tigg's Boom, Moonfire, Alchemist and Bearcat have no alt-fire mode, even though the vast majority of their manufacturer's weapons have.
- The Vortex Grenade utilized by Ruby's Wrath is a variant of the Atlas Tracker Grenade. It is fired at a noticeably higher velocity and will bounce forward instead of stopping on the first impact with terrain. When it explodes, it creates an effect identical to a singularity grenade in addition to tracking all enemies in range.
- The Malak's Bane and ASMD switch between different projectiles.
- The Hornet, Hellfire, Crader's EM-P5 and Good Juju are all locked to a specific firing mechanism and changing the fire mode only adjusts the zoom level of the sight (if it has one).
- The Brashi's Dedication, a Dahl Sniper Rifle, switches between shock and corrosive.
- The Freeman's fired rockets are laser-guided and will move to wherever the cursor points to and lacks the conventional tracking feature of most Atlas Launchers. It has no alt-fire mode as a result.
- The Vosk's Deathgrip alt-fire shoots a puck that creates a singularity.
- The speed at which alternate fire modes are selected is determined by the weapon's Handling statistic. This can be improved with Moze's Scrappy skill.
- Atlas Tracking rounds, Vladof Tasers and special rockets are affected by Moze's Cloud of Lead skill. This allows them to fire multiple times, which may have varying effects:
- Atlas tracking rounds are not affected.
- Vladof tasers and special rockets, upon triggering the skill, will fire a free round.