Augmentation Guide – MHW Companion

The weapon augmentation can be used to improve weapons beyond their last crafting upgrade. However, to use weapon augmentation you first need to fulfill the following requirements:

Complete the story
Reach hunter rank 29
Complete the quest ‘ Beyond the Blasting Scales’
Find a Sullied Streamstone (rare reward for defeating a threat level 2 tempered monster)
or find a Shining Streamstone (rare reward for defeating a threat level 3 tempered monster)

Sullied Streamstones will be identified as Warrior’s Streamstones and Shining Streamstones as Hero’s Streamstones.
Both Streamstone types have additional categories. Depending on their category they can only be used for a specific weapon type:

Sword:	Great Sword, Long Sword
Blade:	Sword and Shield, Dual Blades
Hammer:	Hammer, Hunting Horn
Lance:	Lance, Gunlance
Axe:	Switch Axe, Charge Blade
Shaft:	Insect Glaive, Bow
Ranged:	Light Bowgun, Heavy Bowgun

Warrior’s Streamstones can be used to augment weapons with rarity 6 and 7. Hero’s Streamstones can be used to augment weapons with rarity 8.
Rarity 6 weapons have three augmentation slots, rarity 7 weapons have two augmentation slots and rarity 8 weapons have one augmentation slot.
Each augmentation slot can get one of these augmentation types:

Attack Increase:
Increases attack power (+5 for the true attack value). Stacks with other upgrades of the same type.
Affinity Increase:
Increases affinity (+10% for the first and +5% for the second and third upgrade). Stacks with other upgrades of the same type.
Defense Increase:
Increases defense (+10) and adds a chance to reduce damage taken each time you receive damage. Stacks with other upgrades of the same type.
Slot Upgrade:
Adds an extra slot. Stacks with other upgrades of the same type to increase the slot level.
Health Regen:
Regain health as you land attacks. Stacks with other upgrades of the same type to increase the amount of health regained.