Weapon Mods are one of the biggest progression systems in Killing Floor 3. While new weapons are powerful on their own, crafting and upgrading mods lets you customise them with better stats, improved handling, larger magazines, specialised ammunition, and other useful bonuses.
If you’re also hunting achievements, you’ll need to understand this system to unlock In Mod We Trust, Smooth Upgrader, and Maximalist.
This guide explains how weapon mod crafting works, where to get crafting materials, and the fastest way to unlock every related achievement.
Killing Floor 3 Weapon Mod Crafting Guide: How to Craft, Upgrade & Unlock Every Weapon Mod Achievement
Unlike previous entries in the series, almost all progression in Killing Floor 3 happens through your Stronghold.
The Stronghold acts as your central hub between missions, where you’ll manage your loadouts, skills, and equipment.
To start crafting weapon mods, head into the Armory, which is located in its own room inside the Stronghold.
Here you’ll be able to:
- Create weapon loadouts.
- Equip attachments.
- Craft new weapon mods.
- Upgrade existing mods.
- Swap different weapon components.
As you continue completing missions, you’ll naturally unlock more materials needed for crafting.
What Can You Modify?
Most weapons support a variety of different modifications depending on the weapon type.
Some examples include:
- Ammunition
- Magazines
- Barrels
- Receivers
- Grips
- Blades
- Pommels
- Underbarrel Attachments
- Sights
- Weapon Coatings
Each modification changes your weapon in different ways, allowing you to customise your preferred playstyle.
How to Get Crafting Materials
Crafting materials are earned simply by playing the game.
Most resources drop after defeating specific Zeds, while others are rewarded for destroying environmental objects such as cameras and security equipment.
Since you’ll naturally collect materials while completing missions, there’s no dedicated crafting mode.
If you’re missing one specific resource, however, it helps to know which enemies drop it.
All Crafting Materials
| Crafting Material | Used For | Common Sources |
|---|---|---|
| Bio Sample | Ammo Pouches, Grips, Magazines | Gorefasts, Husks, Sirens, Kiosks, Satcoms |
| Bio Steel | Barrels, Blades, Pommels, Receivers, Sights | Gorefasts, Husks, Sirens, Kiosks, Satcoms |
| Chemical Agent | Ammo Types, Coatings, Underbarrel Attachments | Cysts, Clots, Crawlers |
| Electrical Parts | Barrels, Receivers, Sights | Clots, Gorefasts, Cameras, Loudspeakers, Power Walls |
| Gray Matter | Ammo Types, Ammo Pouches, Coatings, Grips, Magazines, Underbarrel Attachments | Bloats, Husks, Sirens |
| Ichor | Level 3 Weapon Mod Upgrades | Chimera, Impaler, Queen Crawler |
| Scrap Metal | Blades, Pommels, Receivers | Clots, Gorefasts, Cameras, Loudspeakers, Power Walls |
| Zed Tech | Level 2 Weapon Mod Upgrades | Scrakes, Fleshpounds |
Since several enemies drop multiple materials, don’t worry too much about farming early on. Most resources accumulate naturally while playing.
Best Way to Farm Crafting Materials
If you’re specifically trying to unlock weapon mod achievements, these tips will speed things up:
- Complete missions instead of quitting early.
- Kill every special Zed you encounter.
- Destroy security cameras whenever possible.
- Break environmental objects like kiosks and loudspeakers.
- Prioritise Scrakes and Fleshpounds when farming higher-tier upgrades.
- Don’t ignore boss encounters, as some rare materials only come from late-game enemies.
The more enemies you eliminate during each match, the faster your crafting inventory will grow.
In Mod We Trust Achievement
Requirement: Craft your first weapon mod.
This is the easiest weapon-related achievement in the game.
Simply:
- Visit the Armory.
- Select any weapon.
- Choose a weapon modification.
- Craft it once you’ve collected the required materials.
It doesn’t matter which attachment you create.
As soon as your first weapon mod is crafted, the achievement will unlock.
Smooth Upgrader Achievement
Requirement: Upgrade a weapon mod once.
After crafting your first attachment, return to the same mod.
Instead of crafting another copy, choose the Upgrade option.
If you have enough crafting materials, upgrade the mod to the next level.
Once the upgrade finishes, you’ll unlock Smooth Upgrader.
Common Mistake
Many players accidentally craft another attachment instead of upgrading their existing one.
Make sure you’re selecting the already-crafted mod before choosing the upgrade option.
Maximalist Achievement
Requirement: Upgrade a weapon mod to its maximum level.
This achievement takes the longest because you’ll need enough rare crafting materials to fully upgrade a single attachment.
Weapon mods progress through several upgrade stages before reaching their maximum tier.
Simply keep upgrading the same attachment until it reaches its highest level.
Once it’s fully upgraded, Maximalist will unlock automatically.
The biggest obstacle isn’t difficulty—it’s simply collecting enough crafting resources.
Which Mod Should You Upgrade?
If you’re only interested in unlocking achievements, it’s usually better to focus all your materials on a single attachment.
Spreading resources across several different mods slows your overall progress.
Instead:
- Pick a weapon you use regularly.
- Craft one useful attachment.
- Continue upgrading that attachment until it’s fully maxed.
This approach unlocks all three achievements with the least amount of farming.
Tips for Faster Progress
If you’re starting fresh, these tips will help you unlock every weapon mod achievement sooner:
- Visit the Armory after every few missions to spend your materials.
- Upgrade one attachment instead of several.
- Destroy environmental objects whenever possible for extra resources.
- Farm Scrakes and Fleshpounds once you need Zed Tech.
- Save rare materials like Ichor for your highest-level upgrades.
Staying focused on one weapon mod makes the achievement grind much shorter.
Weapon mods add a satisfying layer of progression to Killing Floor 3, letting you tailor your favourite weapons to suit your playstyle while steadily making them more powerful. Although crafting materials may seem overwhelming at first, you’ll gather most of them naturally just by completing missions and defeating tougher Zeds.
If your goal is to unlock every related achievement, the process is straightforward: craft a single weapon mod to earn In Mod We Trust, upgrade it once for Smooth Upgrader, and continue investing materials into that same mod until it reaches its maximum tier for Maximalist. With a little patience and regular gameplay, you’ll have all three achievements unlocked without needing to go out of your way.