During the Gears of War: E-Day campaign, weapon mods let you adjust individual guns, affecting accuracy, reload behavior, ammo type, magazine capacity and other traits. Each weapon has a Perfect Reload row and three numbered mod slots; most slots require an unlock before you can use them. Here’s how the system works, where to get mods and slot unlocks, and what each weapon can receive.
Quick answer: Every weapon starts with slot 1 open and slots 2 and 3 locked. Find a “General Mod Slot” reward for that weapon in a Hard Case or Secondary Objective to open them, then register and fit mods at a Supply Cache.
How mod slots work on each weapon
Each weapon’s mod screen has the same layout. A separate, unnumbered Perfect Reload row sits at the top and changes what a Perfect Reload grants. Most guns begin with Full Metal Jacket there, which adds Perfect Ammo damage. Below it are three slots numbered 1, 2 and 3.
Slot 1 is open from the start. Slots 2 and 3 read SLOT LOCKED until you find the matching unlock for that specific gun. Each slot shows EMPTY, SLOT LOCKED, or a fitted mod with short plus and minus lines such as “++ Accuracy” or “– Damage”. Opening a slot shows GENERAL MODS with a found/total counter and groups the mods under MISC, BARREL, MAGAZINE, STOCK, SCOPE, BODY and AMMO headings. A fitted mod carries the label “EQUIPPED IN MOD SLOT: 1” (or 2, 3).
The Prototype Lancer, Gut-Puncher, Snub, Hammerburst, Gnasher and Breechshot all begin with slot 1 empty and slots 2 and 3 locked. The Lancer Mk1 is the exception, starting with Police Receiver (“+++ Accuracy”, “– Damage”) already fitted in slot 1.
Where mods and mod slots come from
Mods and slot unlocks arrive from two places: yellow Hard Cases lying around the levels, and finishing Secondary Objectives. The system opens in Act 2, Chapter 2, Hold the Line, at the first Supply Cache outside the stadium. The tutorial card that appears there reads: “You now have access to Weapon Mods in the Supply Cache.” It tells you to find Hard Cases and finish Secondary Objectives to unlock new Weapon Mods and Mod Slots, and to customize your weapons at Supply Caches, where each weapon is saved with its configuration.
Hard Cases are yellow cases on the ground. Press X to “Open Hard Case”, and a gold banner names each reward in turn at the top of the screen, with small dots above it showing how many items are inside. “HARD CASE EMPTIED” appears on the left once it is done. A single case can give one or more things. Every reward is tied to one named weapon, written like “HOLO SIGHT / HAMMERBURST MOD”, so rewards often arrive for guns you are not currently holding and simply wait for you in the cache.
Finishing a Secondary Objective pays out the same gold banners. Two early objectives in Hold the Line hand over “BAYONET / HAMMERBURST MOD” and “COVER BRACE / LANCER MK1 MOD”, then later “PRECISION LONG BARREL / BREECHSHOT MOD” and “BAYONET / GNASHER MOD”. After a pickup you may see the card “SUPPLY CACHE REMINDER / Get back to a Supply Cache to register and equip your mods.”
A reward marked “GENERAL MOD SLOT” followed by a weapon name unlocks that gun’s next slot. At the next Supply Cache you visit, slot 2 will appear as EMPTY. Unlocking slot 3 takes another reward for that same weapon. By Act 4, the Prototype Lancer and Snub have all three slots available, but the Gut-Puncher’s third slot remains locked. Tactical Gear and armor also have separate slot rewards and mods, which you install in the same way.
A mod unlock and an available slot are separate requirements. You must register and equip the mod at a Supply Cache before it has an effect, and your number of equipped mods cannot exceed your unlocked slots.
Fitting mods at a Supply Cache
When two mods conflict
Some mods cannot be fitted together. With Forged Barrel in the Snub’s slot 1, highlighting Precision Long Barrel for slot 2 adds a yellow diamond and the warning “This mod conflicts with one of your currently equipped mods.” The prompt switches from A Equip Mod to A Replace Conflicting Mod, and the clashing fitted mod picks up the same yellow diamond.
Forged Barrel and Precision Long Barrel both belong to BARREL, so mods assigned to the same gun part conflict. Mods in separate categories can be used together: examples include Forged Barrel with Extended Magazine on the Snub, and Precision Rifling, Active Compensator and Skeleton Frame on the Prototype Lancer. MISC mods do not count as one shared gun part; for instance, Slick Breech and Auto-Pouch can both be equipped on the Gnasher without a warning.
Every weapon mod seen, by weapon
The lists below cover the mods confirmed on each gun. The cache counters show more exist than are shown here (the Prototype Lancer, for example, reads 10 of 15 general mods found). Where a mod was only seen as a pickup banner, its name is listed without an effect, because its description screen was never opened.
Prototype Lancer
| Mod | Slot | Effect |
|---|---|---|
| Full Metal Jacket | Perfect Reload | ++ Perfect Ammo damage |
| Chainsaw Autoloader | Misc | A chainsaw execution awards a Perfect Reload. |
| Chainsaw Extractor | Misc | Chainsaw executions leave behind a small ammo refill. |
| Chainsaw Supercharger | Misc | Chainsaw revs up faster |
| Precision Rifling | Barrel | Increased critical damage and accuracy |
| Active Compensator | Stock | Steadily increasing accuracy during sustained fire |
| Cover Brace | Stock | Accuracy improves greatly when you fire from cover. |
| Holo Sight | Scope | 1.3x toggle zoom, slightly increased accuracy |
| Tactical Scope | Scope | Ranged scope, 2x to 4.5x toggle zoom |
| Huge Magazine | Magazine | Greatly increased capacity, slower aim and reload |
| Skeleton Frame | Body | Improved aim and swap speed, faster aimed movement |
Snub
| Mod | Slot | Effect |
|---|---|---|
| Full Metal Jacket | Perfect Reload | ++ Perfect Ammo damage |
| Double-Tap Burst | Misc | Two-round burst, faster fire, less range and accuracy |
| Laser | Misc | A visible dot appears on the reticle whenever you are not aiming. |
| Forged Barrel | Barrel | Increased accuracy and damage range |
| Precision Long Barrel | Barrel | More critical damage, accuracy, shots pierce targets |
| Extended Magazine | Magazine | Increased capacity (reserve 132 to 136) |
| Aim Stabilizer | Stock | Increased accuracy when aiming |
Gut-Puncher
| Mod | Slot | Effect |
|---|---|---|
| Shaped Charge | Perfect Reload | Perfect Ammo with increased damage |
| Overcharged Ammo | Perfect Reload | Perfect Reloads provide Perfect Ammo with a larger explosion radius. |
| Acid Rounds | Ammo | Creates a persistent acid hazard that damages enemies |
| Concussion Rounds | Ammo | Larger area, inflicts Stunned, deals no damage |
| Incendiary Rounds | Ammo | Creates a persistent fire hazard that ignites enemies |
| Extended Belt | Magazine | Increased capacity (12 to 14) |
Gnasher
| Mod | Slot | Effect |
|---|---|---|
| Full Metal Jacket | Perfect Reload | ++ Perfect Ammo damage |
| Slick Breech | Misc | Greatly increased reload speed |
| Bayonet | Misc | Adds a bayonet for quick attacks and bayonet charge |
| Auto-Pouch | Misc | Reloads automatically after being stowed briefly |
| Composite Chassis | Body | Flinch and sway are reduced while aiming or looking through a scope. |
| Skeleton Frame | Body | Improved aim and swap speed, faster aimed movement |
Springloaded Mag (Perfect Reload) and High Capacity Mag were also picked up for the Gnasher as reward banners.
Lancer Mk1
The Lancer Mk1 uses Full Metal Jacket on its Perfect Reload row and starts with Police Receiver (“+++ Accuracy”, “– Damage”) already in slot 1. Picked up for it as reward banners: Cover Brace, Extended Magazine and Cut Magwell.
Hammerburst
For the Hammerburst, Springloaded Mag is the Perfect Reload mod, with the effect “++ Perfect Ammo fire rate”. Its reward banners include Bayonet, Incendiary Ammo, Holo Sight, Huge Magazine, Composite Chassis and Mobile Stabilizer.
Breechshot
The Breechshot uses Full Metal Jacket on its Perfect Reload row. Picked up for it as reward banners: Precision Long Barrel, Hardened Ammo, Combat Scope and Skeleton Frame.
Longshot
The Longshot carries Full Metal Jacket on its Perfect Reload row and holds Marksman Scope (“3x single zoom”, “+ Aim speed”) in slot 1. Picked up for it as reward banners: Precision Long Barrel, Forged Barrel, Detonator Ammo and Tactical Scope.
Armor and Tactical Gear mods
The same Hard Cases also hold armor and tactical gear mods, which fit into their own slots in the cache. COG armor mods tune survival and recovery:
- Hardened Cover — improved defense while in cover
- Rock Steady — improved weapon recoil
- Proximity Reload — close-range kills grant a Perfect Reload
- Ammo Scavenger — enemies may drop an ammo magazine when killed
- Proximity Regen — close-range kills heal you
- Best Defense — killing an enemy from cover heals you
- Smooth Operator — improved aim, weapon swap and reload speed
Adrenaline Injector mods are sorted per slot, such as “SLOT 2 MODS 2/4”. Confirmed options include Burst Capacitor (improved cooldown), Regenerative Compound (improved health regeneration with Adrenaline), Fortifying Compound (improved defense with Adrenaline) and Reflex Compound (Active Reload grants a Perfect Reload with Adrenaline). The Sonic Disruptor has Retention Battery, which increases its duration.
Moving, swapping and paying for mods
A mod is tied to its weapon and cannot be moved to another gun. Rewards apply to a specific weapon, even though multiple guns can each have a mod with the same name: Skeleton Frame is available for the Prototype Lancer, Gnasher and Breechshot, while Bayonet is available for the Hammerburst and Gnasher. The mod screens show neither prices nor currency, so campaign mod fitting is free. Replacing a mod does not remove it; it remains listed and can be installed again at any Supply Cache whenever you want to alter your setup.
