diff --git a/src/main/java/electroblob/wizardry/item/ItemFlamecatcher.java b/src/main/java/electroblob/wizardry/item/ItemFlamecatcher.java
index 0e69a622..d8b57e54 100644
--- a/src/main/java/electroblob/wizardry/item/ItemFlamecatcher.java
+++ b/src/main/java/electroblob/wizardry/item/ItemFlamecatcher.java
@@ -1,11 +1,11 @@
 package electroblob.wizardry.item;
 
 import electroblob.wizardry.Wizardry;
-import electroblob.wizardry.client.DrawingUtils;
 import electroblob.wizardry.entity.projectile.EntityFlamecatcherArrow;
 import electroblob.wizardry.registry.Spells;
 import electroblob.wizardry.registry.WizardrySounds;
 import electroblob.wizardry.spell.Flamecatcher;
+import electroblob.wizardry.util.InventoryUtils;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.entity.player.EntityPlayer;
@@ -111,7 +111,7 @@ public class ItemFlamecatcher extends ItemBow implements IConjuredItem {
 	@Override
 	public void onUpdate(ItemStack stack, World world, Entity entity, int slot, boolean selected){
 		int damage = stack.getItemDamage();
-		if(damage > stack.getMaxDamage()) entity.replaceItemInInventory(slot, ItemStack.EMPTY);
+		if(damage > stack.getMaxDamage()) InventoryUtils.replaceItemInInventory(entity, slot, stack, ItemStack.EMPTY);
 		stack.setItemDamage(damage + 1);
 	}
 
diff --git a/src/main/java/electroblob/wizardry/item/ItemFlamingAxe.java b/src/main/java/electroblob/wizardry/item/ItemFlamingAxe.java
index a015fd30..416adefa 100644
--- a/src/main/java/electroblob/wizardry/item/ItemFlamingAxe.java
+++ b/src/main/java/electroblob/wizardry/item/ItemFlamingAxe.java
@@ -4,6 +4,7 @@ import com.google.common.collect.Multimap;
 import electroblob.wizardry.registry.Spells;
 import electroblob.wizardry.spell.Spell;
 import electroblob.wizardry.util.EntityUtils;
+import electroblob.wizardry.util.InventoryUtils;
 import electroblob.wizardry.util.MagicDamage;
 import electroblob.wizardry.util.MagicDamage.DamageType;
 import net.minecraft.entity.Entity;
@@ -81,7 +82,7 @@ public class ItemFlamingAxe extends ItemAxe implements IConjuredItem {
 	@Override
 	public void onUpdate(ItemStack stack, World world, Entity entity, int slot, boolean selected){
 		int damage = stack.getItemDamage();
-		if(damage > stack.getMaxDamage()) entity.replaceItemInInventory(slot, ItemStack.EMPTY);
+		if(damage > stack.getMaxDamage()) InventoryUtils.replaceItemInInventory(entity, slot, stack, ItemStack.EMPTY);
 		stack.setItemDamage(damage + 1);
 	}
 
diff --git a/src/main/java/electroblob/wizardry/item/ItemFrostAxe.java b/src/main/java/electroblob/wizardry/item/ItemFrostAxe.java
index 35ed354b..e9cf5912 100644
--- a/src/main/java/electroblob/wizardry/item/ItemFrostAxe.java
+++ b/src/main/java/electroblob/wizardry/item/ItemFrostAxe.java
@@ -5,6 +5,7 @@ import electroblob.wizardry.registry.Spells;
 import electroblob.wizardry.registry.WizardryPotions;
 import electroblob.wizardry.spell.Spell;
 import electroblob.wizardry.util.EntityUtils;
+import electroblob.wizardry.util.InventoryUtils;
 import electroblob.wizardry.util.MagicDamage;
 import electroblob.wizardry.util.MagicDamage.DamageType;
 import net.minecraft.entity.Entity;
@@ -83,7 +84,7 @@ public class ItemFrostAxe extends ItemAxe implements IConjuredItem {
 	@Override
 	public void onUpdate(ItemStack stack, World world, Entity entity, int slot, boolean selected){
 		int damage = stack.getItemDamage();
-		if(damage > stack.getMaxDamage()) entity.replaceItemInInventory(slot, ItemStack.EMPTY);
+		if(damage > stack.getMaxDamage()) InventoryUtils.replaceItemInInventory(entity, slot, stack, ItemStack.EMPTY);
 		stack.setItemDamage(damage + 1);
 	}
 
diff --git a/src/main/java/electroblob/wizardry/item/ItemLightningHammer.java b/src/main/java/electroblob/wizardry/item/ItemLightningHammer.java
index f8bb19e9..9c6aa979 100644
--- a/src/main/java/electroblob/wizardry/item/ItemLightningHammer.java
+++ b/src/main/java/electroblob/wizardry/item/ItemLightningHammer.java
@@ -7,6 +7,7 @@ import electroblob.wizardry.registry.WizardrySounds;
 import electroblob.wizardry.spell.LightningHammer;
 import electroblob.wizardry.spell.Spell;
 import electroblob.wizardry.util.EntityUtils;
+import electroblob.wizardry.util.InventoryUtils;
 import electroblob.wizardry.util.MagicDamage;
 import electroblob.wizardry.util.MagicDamage.DamageType;
 import electroblob.wizardry.util.ParticleBuilder;
@@ -112,7 +113,7 @@ public class ItemLightningHammer extends Item implements IConjuredItem {
 	@Override
 	public void onUpdate(ItemStack stack, World world, Entity entity, int slot, boolean selected){
 		int damage = stack.getItemDamage();
-		if(damage > stack.getMaxDamage()) entity.replaceItemInInventory(slot, ItemStack.EMPTY);
+		if(damage > stack.getMaxDamage()) InventoryUtils.replaceItemInInventory(entity, slot, stack, ItemStack.EMPTY);
 		stack.setItemDamage(damage + 1);
 	}
 
diff --git a/src/main/java/electroblob/wizardry/item/ItemSpectralBow.java b/src/main/java/electroblob/wizardry/item/ItemSpectralBow.java
index 0bbad2b8..7ba0e290 100644
--- a/src/main/java/electroblob/wizardry/item/ItemSpectralBow.java
+++ b/src/main/java/electroblob/wizardry/item/ItemSpectralBow.java
@@ -2,6 +2,7 @@ package electroblob.wizardry.item;
 
 import electroblob.wizardry.Wizardry;
 import electroblob.wizardry.registry.Spells;
+import electroblob.wizardry.util.InventoryUtils;
 import net.minecraft.enchantment.EnchantmentHelper;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.EntityLivingBase;
@@ -105,7 +106,7 @@ public class ItemSpectralBow extends ItemBow implements IConjuredItem {
 	@Override
 	public void onUpdate(ItemStack stack, World world, Entity entity, int slot, boolean selected){
 		int damage = stack.getItemDamage();
-		if(damage > stack.getMaxDamage()) entity.replaceItemInInventory(slot, ItemStack.EMPTY);
+		if(damage > stack.getMaxDamage()) InventoryUtils.replaceItemInInventory(entity, slot, stack, ItemStack.EMPTY);
 		stack.setItemDamage(damage + 1);
 	}
 
diff --git a/src/main/java/electroblob/wizardry/item/ItemSpectralPickaxe.java b/src/main/java/electroblob/wizardry/item/ItemSpectralPickaxe.java
index b48ae2b2..90ba3264 100644
--- a/src/main/java/electroblob/wizardry/item/ItemSpectralPickaxe.java
+++ b/src/main/java/electroblob/wizardry/item/ItemSpectralPickaxe.java
@@ -1,6 +1,7 @@
 package electroblob.wizardry.item;
 
 import electroblob.wizardry.registry.Spells;
+import electroblob.wizardry.util.InventoryUtils;
 import net.minecraft.block.state.IBlockState;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.player.EntityPlayer;
@@ -62,7 +63,7 @@ public class ItemSpectralPickaxe extends ItemPickaxe implements IConjuredItem {
 	@Override
 	public void onUpdate(ItemStack stack, World world, Entity entity, int slot, boolean selected){
 		int damage = stack.getItemDamage();
-		if(damage > stack.getMaxDamage()) entity.replaceItemInInventory(slot, ItemStack.EMPTY);
+		if(damage > stack.getMaxDamage()) InventoryUtils.replaceItemInInventory(entity, slot, stack, ItemStack.EMPTY);
 		stack.setItemDamage(damage + 1);
 	}
 
diff --git a/src/main/java/electroblob/wizardry/item/ItemSpectralSword.java b/src/main/java/electroblob/wizardry/item/ItemSpectralSword.java
index 345cac72..a21a4c77 100644
--- a/src/main/java/electroblob/wizardry/item/ItemSpectralSword.java
+++ b/src/main/java/electroblob/wizardry/item/ItemSpectralSword.java
@@ -3,6 +3,7 @@ package electroblob.wizardry.item;
 import com.google.common.collect.Multimap;
 import electroblob.wizardry.registry.Spells;
 import electroblob.wizardry.util.EntityUtils;
+import electroblob.wizardry.util.InventoryUtils;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.SharedMonsterAttributes;
 import net.minecraft.entity.ai.attributes.AttributeModifier;
@@ -77,7 +78,7 @@ public class ItemSpectralSword extends ItemSword implements IConjuredItem {
 	@Override
 	public void onUpdate(ItemStack stack, World world, Entity entity, int slot, boolean selected){
 		int damage = stack.getItemDamage();
-		if(damage > stack.getMaxDamage()) entity.replaceItemInInventory(slot, ItemStack.EMPTY);
+		if(damage > stack.getMaxDamage()) InventoryUtils.replaceItemInInventory(entity, slot, stack, ItemStack.EMPTY);
 		stack.setItemDamage(damage + 1);
 	}
 
diff --git a/src/main/java/electroblob/wizardry/util/InventoryUtils.java b/src/main/java/electroblob/wizardry/util/InventoryUtils.java
index 438458e0..acb3bb42 100644
--- a/src/main/java/electroblob/wizardry/util/InventoryUtils.java
+++ b/src/main/java/electroblob/wizardry/util/InventoryUtils.java
@@ -1,5 +1,6 @@
 package electroblob.wizardry.util;
 
+import net.minecraft.entity.Entity;
 import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.EntityEquipmentSlot;
@@ -10,6 +11,7 @@ import net.minecraft.nbt.NBTTagCompound;
 import net.minecraft.util.EnumHand;
 import net.minecraft.util.EnumHandSide;
 import net.minecraft.util.NonNullList;
+import net.minecraft.world.World;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -142,4 +144,28 @@ public final class InventoryUtils {
 				&& ItemStack.areItemStackTagsEqual(stack1, stack2);
 	}
 
+	/**
+	 * A version of {@link Entity#replaceItemInInventory(int, ItemStack)} that takes a slot index specific to the main,
+	 * armour and offhand inventories, as passed to {@link Item#onUpdate(ItemStack, World, Entity, int, boolean)},
+	 * rather than the proper slot index used everywhere else (just <i>why</i>, Mojang?).
+	 * @param entity The entity to replace the item for
+	 * @param slot The slot index to replace
+	 * @param original The item stack currently in the slot (required for technical reasons)
+	 * @param replacement The new item stack
+	 * @return True if an item was replaced, false if not
+	 */
+	public static boolean replaceItemInInventory(Entity entity, int slot, ItemStack original, ItemStack replacement){
+		// Check slots that aren't in the main inventory first by comparing with the existing item
+		if(entity instanceof EntityLivingBase){
+			for(EntityEquipmentSlot eslot : EntityEquipmentSlot.values()){
+				if(((EntityLivingBase)entity).getItemStackFromSlot(eslot) == original){
+					entity.setItemStackToSlot(eslot, replacement);
+					return true;
+				}
+			}
+		}
+		// Otherwise use the normal behaviour
+		return entity.replaceItemInInventory(slot, replacement);
+	}
+
 }