"The Rumbler portable mortar is a heavy piece of equipment and very clunky in its operation. Its clunkiness is tolerated however, mostly because of its immense firepower, but also because it is a variable distance indirect fire weapon. The Rumbler is part of the Weapons equipment kit."
- Armory Description
Stratagem Code
Players must enter the following sequence, using the controller d‑pad, in order to call down this single-use Stratagem during a mission:
Unlock Requirement
The M-25 Rumbler is a DLC weapon, available at any rank to those who purchase the Weapons Pack.
Upgrades
| Upgrade | Cost | Effect | |
|---|---|---|---|
 |
Mk1 | Basic variant, no upgrades. | |
 |
Mk2 |  2 |
A larger autoloading magazine allows more shots before reload. Magazine size increased from 2 to 4. |
 |
Mk3 | 3 |
The weapon now fires toxic grenades that will deal poison damage to anything caught near the detonation. |
Weapon Stats
- The weapon comes with 2 magazines of Rumbler mortar shells, and can carry up to 4. By default, the weapon can fire 2 bursts before requiring a reload; the Mk2 has double the capacity, allowing for 4 bursts between reloads.
- Reloading the Rumbler immobilizes the operator and takes 4.5 seconds to complete.
| M-25 'Rumbler' Detailed Analysis | |||
|---|---|---|---|
| Weapon Info | Additional Notes | ||
| Unlock Rank | Rank 1 | Unlocked via DLC | |
| Weapon Type | Secondary | ||
| Weapon Category | Mortar | ||
| Fire Mode | Salvo fire, indirect fire | ||
| Damage | |||
| Base | Upgraded | Additional Notes | |
| Damage | 0 | 0 | |
| Center Mass Damage | 0 | 0 | |
| Anti-Personnel Explosive Damage | 350 | 350 | |
| Anti-Personnel Explosion Radius | 3.5 m | 3.5 m | |
| Direct Explosive Damage | 1800 | 1800 | |
| Direct Explosion Radius | 2.5 m | 2.5 m | |
| Status Effects | None | Heavy Poison; Slow Poison* |
* Requires Mk3 upgrade |
| Heavy Poison Damage/sec | N/A | 100/s* | * Requires Mk3 upgrade; only Heavy Poison damages over time |
| Heavy Poison Duration | N/A | 5 s* | * Requires Mk3 upgrade |
| Poison Slowdown | N/A | -75%* | * Requires Mk3 upgrade |
| Slow Poison Duration | N/A | 6 s* | * Requires Mk3 upgrade |
| AP Ammo Armor Reduction | 0 | 0 | |
| Statistics | |||
| Base | Upgraded | Additional Notes | |
| Cyclic Rate of Fire (RPM) | 66 | 66 | Should be 60, but 66 has been observed |
| Capacity | 2 | 4† | † Requires Mk2 upgrade |
| Starting Mags | 2 | 2 | |
| Max Mags | 4 | 4 | |
| Reload Speed | 4.5 s | 4.5 s | No tactical reload; immobilized while reloading |
| Min Spread | 0° | 0° | |
| Max Spread | 0° | 0° | |
| Spread Increase per Shot | 0° | 0° | |
| Max Range | todo | todo | |
| Bullet Spread Simulation | N/A | ||
Gameplay Tips
- The M-25 Rumbler is the single most devastating man-portable weapon in the entire Helldivers arsenal. Firing high explosive shells in three-round bursts in a variably high arcing trajectory, it is capable of decimating hordes of enemies and destroying every unit and objective in the game. Coupled with its doubled capacity and toxic upgrade when fully researched, the Rumbler offers utility, sheer damage, and crowd control all in one weapon. While extremely potent and capable of putting out a horrific amount of damage in a short period of time, its clunky handling, lengthy reload, and propensity to detonate shells in its users face make it a high-risk-high-reward weapon.
- The Rumbler operates with a mechanic similar to Arc weapons: holding the fire button will greatly decrease turn speed and tilt the mortar up and back, increasing the range and peak height of the shells. After aiming and charging the Rumbler, releasing the fire button will send out a volley of three shells in a tight group; subsequent shells in a volley will land slightly closer to the user relative to the first shell launched. Helldivers can aim and move freely once the first shell has been fired, allowing the second and third shells to be sent in a completely different direction relative to the first shell.
- Thanks to its fixed trajectory, Helldivers can fire over teammates, objectives, and cover to hit enemies without exposing themselves to retaliation. This should be used with extreme caution however as latency and the disjointed hitboxes of environmental features can result in shells detonating the moment they leave the barrel of the gun or too close to teammates or objectives.
- Sweeping while in the middle of a burst with the Rumbler allows it to send three shells in a wide arc, hitting multiple enemies at a time. This is especially useful for crowd control with the Mk 3 toxic upgrade and can even be used to destroy certain Objectives with a single burst. Be mindful of this feature as it can quickly result in accidental deaths and failed objectives.
- The Rumbler requires a minimum charge of 0.33s before it can fire and has a delay of 0.25s before it can begin charging the next volley. With precise timing and good spacing, it is possible to fire all four volleys in quick succession, dealing up to a theoretical maximum of 31,800 damage in the span of two seconds. This gives it the highest spike damage of any weapon in the game and is especially useful against heavy units and faction bosses.
- The Mk3 upgrade adds a powerful toxic agent to the mortar grenades which slows and deals considerable damage over time, crippling any enemy it does not destroy outright. This damage over time can kill a Helldiver three times over, similar to the TOX-13 Avenger and Missile Barrage's Mk 3 toxic effects. Helldivers and Survivors affected by the toxin can still be saved by quickly moving over to them and reviving them three times in quick succession as the poison wears itself out.
- Each grenade fired from the Rumbler is a physical object in the game-world that can collide with various other objects, causing them to explode on contact. Standing too close to walls, trees and other terrain features, and other players can cause the Rumbler's projectiles to explode upon firing, instantly killing the user and any other Helldiver or objective within range. Divers or objectives who survive the initial blast can suffer from the Rumbler's toxic effects if the appropriate upgrade has been bought for the weapon.
- Other causes for the projectiles to explode mid-air include (but are not limited to): being detonated by enemy fire (specifically Cyborg IFV's main battle-cannon and Warlord's gauss-cannon), colliding with ejected shells from a fellow diver's SG-225 Breaker, airborne players using the LIFT-850 Jump Pack (airborne Lift-users remain unaffected from the explosion and resulting status effects), and Static Field Conductors (although this happens inconsistently).
- The Rumbler is capable of destroying mission objectives that would ordinarily require the use of a NUX-223 Hellbomb, such as Bug Nests, Illuminate Beacons and Cyborg AA Guns. Cyborg IFVs must be hit in the rear to be destroyed and AA guns and Beacons must be hit directly on their foundations, but all other heavily armored enemies are easily dealt with regardless of the point of impact.
Gallery
M-25 Rumbler
Helldiver launching three toxic shells
Notes
| Weapons | ||||||||
|---|---|---|---|---|---|---|---|---|
| Sidearms | Assault rifles | LMGs | Shotguns | SMGs | Precision | Explosive | Laser tech | Arc tech |
| P-2 Peacemaker | AR-19 Liberator | MG-105 Stalwart♦ | SG-225 Breaker | SMG-45 Defender | LHO-63 Camper♦ | CR-9 Suppressor♦ | LAS-5 Scythe | AC-3 Arc Thrower |
| P-6 Gunslinger♦ | AR-22C Patriot | SG-8 Punisher | MP-98 Knight SMG | RX-1 Rail Gun | PLAS-1 Scorcher♦ | LAS-16 Sickle♦ | AC-5 Arc Shotgun♦ | |
| FLAM-24 Pyro♦ | AR-20L Justice | DBS-2 Double Freedom | SMG-34 Ninja♦ | M2016 Constitution | LAS-12 Tanto♦ | |||
| PLAS-3 Singe♦ | AR-14D Paragon♦ | LAS-13 Trident | ||||||
| Heavy Weapons | ||||||||
|
MG-94 Machine Gun – MGX-42 Machine Gun – AC-22 Dum-Dum♦ – LAS-98 Laser Cannon – FLAM-40 Incinerator – TOX-13 Avenger♦ Obliterator Grenade Launcher – MLS-4X Commando♦ – RL-112 Recoilless Rifle – EAT-17 – REC-6 Demolisher♦ – M-25 Rumbler♦ | ||||||||