diff --git a/pom.xml b/pom.xml
index e4040879..94ffa2ac 100644
--- a/pom.xml
+++ b/pom.xml
@@ -81,6 +81,10 @@
     </build>
 
     <repositories>
+        <repository>
+            <id>phoenix</id>
+            <url>http://la-grange-evasion.pro.dns-orange.fr:8081/</url>
+        </repository>
 
         <repository>
             <id>lumine</id>
@@ -143,7 +147,7 @@
         <dependency>
             <groupId>io.lumine</groupId>
             <artifactId>MythicLib-dist</artifactId>
-            <version>1.3.4</version>
+            <version> 1.3.4</version>
             <scope>provided</scope>
         </dependency>
 
diff --git a/src/main/java/net/Indyuce/mmocore/experience/source/KillMobExperienceSource.java b/src/main/java/net/Indyuce/mmocore/experience/source/KillMobExperienceSource.java
index 96c3a7be..a1c28452 100644
--- a/src/main/java/net/Indyuce/mmocore/experience/source/KillMobExperienceSource.java
+++ b/src/main/java/net/Indyuce/mmocore/experience/source/KillMobExperienceSource.java
@@ -1,5 +1,6 @@
 package net.Indyuce.mmocore.experience.source;
 
+import com.guillaumevdn.questcreator.lib.event.PlayerKillEntityEvent;
 import io.lumine.mythic.lib.api.MMOLineConfig;
 import io.lumine.mythic.lib.api.event.PlayerKillEntityEvent;
 import net.Indyuce.mmocore.MMOCore;
@@ -9,10 +10,12 @@ import net.Indyuce.mmocore.experience.source.type.SpecificExperienceSource;
 import net.Indyuce.mmocore.manager.profession.ExperienceSourceManager;
 import net.Indyuce.mmocore.api.player.PlayerData;
 import org.bukkit.Bukkit;
+import org.bukkit.NamespacedKey;
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.EntityType;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
+import org.bukkit.persistence.PersistentDataType;
 
 public class KillMobExperienceSource extends SpecificExperienceSource<Entity> {
     public final EntityType type;
@@ -30,12 +33,12 @@ public class KillMobExperienceSource extends SpecificExperienceSource<Entity> {
             @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
             public void a(PlayerKillEntityEvent event) {
                 Bukkit.getScheduler().runTaskLater(MMOCore.plugin, () -> {
-                    if (event.getTarget().isDead() && !event.getTarget().hasMetadata("spawner_spawned")) {
+                    if (event.getKilled().isDead() && !event.getKilled().getPersistentDataContainer().has(new NamespacedKey(MMOCore.plugin,"spawner_spawned"),PersistentDataType.STRING)) {
                         PlayerData data = PlayerData.get(event.getPlayer());
 
                         for (KillMobExperienceSource source : getSources())
-                            if (source.matches(data, event.getTarget()))
-                                source.giveExperience(data, 1, MMOCoreUtils.getCenterLocation(event.getTarget()));
+                            if (source.matches(data, event.getKilled()))
+                                source.giveExperience(data, 1, MMOCoreUtils.getCenterLocation(event.getKilled()));
                     }
                 }, 2);
             }
diff --git a/src/main/java/net/Indyuce/mmocore/listener/option/NoSpawnerEXP.java b/src/main/java/net/Indyuce/mmocore/listener/option/NoSpawnerEXP.java
index d5382c8c..e819b9ba 100644
--- a/src/main/java/net/Indyuce/mmocore/listener/option/NoSpawnerEXP.java
+++ b/src/main/java/net/Indyuce/mmocore/listener/option/NoSpawnerEXP.java
@@ -1,16 +1,19 @@
 package net.Indyuce.mmocore.listener.option;
 
 import net.Indyuce.mmocore.MMOCore;
+import org.bukkit.NamespacedKey;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.Listener;
 import org.bukkit.event.entity.CreatureSpawnEvent;
 import org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason;
 import org.bukkit.metadata.FixedMetadataValue;
+import org.bukkit.persistence.PersistentDataType;
 
 public class NoSpawnerEXP implements Listener {
 	@EventHandler
 	public void a(CreatureSpawnEvent event) {
 		if(event.getSpawnReason() == SpawnReason.SPAWNER)
+			event.getEntity().getPersistentDataContainer().set(new NamespacedKey(MMOCore.plugin,"spawner_spawned"), PersistentDataType.STRING,"true");
 			event.getEntity().setMetadata("spawner_spawned", new FixedMetadataValue(MMOCore.plugin, true));
 	}
 }
diff --git a/src/main/java/net/Indyuce/mmocore/loot/droptable/dropitem/DropItem.java b/src/main/java/net/Indyuce/mmocore/loot/droptable/dropitem/DropItem.java
index b84e5cc3..17f10cb6 100644
--- a/src/main/java/net/Indyuce/mmocore/loot/droptable/dropitem/DropItem.java
+++ b/src/main/java/net/Indyuce/mmocore/loot/droptable/dropitem/DropItem.java
@@ -10,6 +10,7 @@ import io.lumine.mythic.lib.api.MMOLineConfig;
 public abstract class DropItem {
     protected static final Random random = new Random();
 
+    private static final double CHANCE_COEFFICIENT = 7. / 100;
     private final double chance, weight;
     private final RandomAmount amount;
 
@@ -35,11 +36,19 @@ public abstract class DropItem {
         return amount.calculateInt();
     }
 
+    /**
+     * CHANCE stat = 0    | tier chances are unchanged
+     * CHANCE stat = +inf | uniform law for any drop item
+     * CHANCE stat = 100  | all tier chances are taken their square root
+     *
+             * @return The real weight of an item considering the player's CHANCE stat.
+            */
     /**
      * If the player chance is 0 the random value will remain the same. When he get lucks the chance gets closer to one.
      */
     public boolean rollChance(PlayerData player) {
-        return Math.pow(random.nextDouble(), 1 / Math.log(1 + player.getStats().getStat("CHANCE"))) < chance;
+        double value=random.nextDouble();
+        return value< Math.pow(chance, 1 / Math.pow(1 + CHANCE_COEFFICIENT * player.getStats().getStat("CHANCE"), 1.0 / 3.0));
     }
 
     public abstract void collect(LootBuilder builder);