diff --git a/maps/mountain_fortress_v3/functions.lua b/maps/mountain_fortress_v3/functions.lua
index 49af43b2..cff1ca46 100644
--- a/maps/mountain_fortress_v3/functions.lua
+++ b/maps/mountain_fortress_v3/functions.lua
@@ -1469,7 +1469,7 @@ function Public.on_research_finished(event)
     local player = game.forces.player
 
     research.force.character_inventory_slots_bonus = player.mining_drill_productivity_bonus * 50 -- +5 Slots /
-    bonus_drill.mining_drill_productivity_bonus = bonus_drill.mining_drill_productivity_bonus + 0.1
+    bonus_drill.mining_drill_productivity_bonus = bonus_drill.mining_drill_productivity_bonus + 0.03
     if bonus_drill.mining_drill_productivity_bonus >= 3 then
         bonus_drill.mining_drill_productivity_bonus = 3
     end
diff --git a/maps/mountain_fortress_v3/main.lua b/maps/mountain_fortress_v3/main.lua
index c5dff645..5389fd54 100644
--- a/maps/mountain_fortress_v3/main.lua
+++ b/maps/mountain_fortress_v3/main.lua
@@ -112,7 +112,7 @@ local init_bonus_drill_force = function()
     end
     bonus_drill.set_friend('player', true)
     player.set_friend('bonus_drill', true)
-    bonus_drill.mining_drill_productivity_bonus = 1
+    bonus_drill.mining_drill_productivity_bonus = 0.5
 end
 
 local is_position_near_tbl = function(position, tbl)