You need to craft a better weapon holster. It's the same process on how you got the 2 weapon holster; you got a Goat skin and crafted it, you. How to unlock your weapons slots in Far Cry 3. As you can see only one of slots is unlocked, meaning you. To get more slots for weapons, you must craft Weapon Holsters using animal hides. If you go to Crafting and then to Weapon Holsters it should tell you what.
Far Cry 4: How To Upgrade Weapon Holster to Tier 1,2,3 - Quick Complete Guide
Far cry 3 weapon slots - Aktivierung