Borderlands 4 - Instant Underbarrel Cooldown Bug @BippoErnesti
Borderlands 4 - Instant Underbarrel Cooldown Bug  @BippoErnesti
Uploaded September 2025 | Updated September 2026, 1 week ago
Another bug I noticed where, if you have appropriate stuff that ups your underbarrel magazine size, it instantly refills your underbarrel on weapon/mode switch if you only fire the extra in it. Basically, if you have an underbarrel with 100 ammo and you have something that ups it to 120, you can freely spend the 20 ammo and cycle weapons to instantly get it back; utterly deadly with stuff like a multi-shot Taser attachment. If you fire too many shots, you will induce a standard cooldown and need to wait it out (22s for the weapon I was using), so it's worth being careful.

Basic how-to:
1. Get a weapon with an underbarrel/alt-fire
2. Equip something that increases your magazine size enough to affect the max underbarrel ammo (not all parts work)
3. Fire only the excess
4. Cycle between another weapon (or toggle alt-fire) and back to reset it

Also worth noting that I'm not 100% sure which types of gear increase underbarrel magazine size. For example, a general "Gun Magazine Size" increase in something like an Enhancement doesn't seem to affect the alt-fire, I've only seen underbarrel mag size increase with the Box Magazine part on Vladof Enhancements which specifically affects Vladof-licensed guns, and Amon's Scorched Kairos tier 1 blue skill, which is up to +30% mag size to any gun.

Chapters
0:00 Example item combo
0:16 Demonstrating the bug
0:43 Erasing/tasing a world boss
Borderlands 4 - Instant Underbarrel Cooldown BugSuper Mario 64 - 120 Star Playthrough (Archive* [2024])Super Mario 64 Randomizer (v1.1.2) - 120 Star Playthrough [*Archive]Mega Man 11 - 04 - Tundra Man + Midpoint CutsceneFinal Fantasy VII Remake No-Summon/Magic Playthrough [Archivepart 3b] (Archive*)The Elder Scrolls V: Skyrim (Special Edition) - Dragon-Inflicted Flying Horse GlitchSuper Mario Maker 2 - Ninji Speedrun: Headgear Hustle (0:32.523)Super Mario Maker 2 - Custom Course: Typical TravellingSuper Mario Maker 2 - Custom Course: Rapacitys SnareFinal Fantasy III Pixel Remaster - Final Battle & EndingLast Call/Happy Hour (PC Game) Music RipSuper Mario Maker 2 - Custom Course: Yoink
Bippo Ernesti |

Borderlands 4 - Instant Underbarrel Cooldown Bug

SHARE TO X SHARE TO REDDIT SHARE TO FACEBOOK WALLPAPER