diff --git a/api/src/main/java/kr/toxicity/model/api/armor/PlayerArmor.java b/api/src/main/java/kr/toxicity/model/api/armor/PlayerArmor.java
index 23e103da9..b212c2c40 100644
--- a/api/src/main/java/kr/toxicity/model/api/armor/PlayerArmor.java
+++ b/api/src/main/java/kr/toxicity/model/api/armor/PlayerArmor.java
@@ -7,6 +7,7 @@
 
 package kr.toxicity.model.api.armor;
 
+import kr.toxicity.model.api.util.TransformedItemStack;
 import org.jetbrains.annotations.Nullable;
 
 /**
@@ -45,6 +46,25 @@ public interface PlayerArmor {
      */
     @Nullable ArmorItem helmet();
 
+    /**
+     * Gets the custom item-model stack worn in the helmet slot.
+     * <p>
+     * A {@code null} value means the helmet should use BetterModel's generated
+     * vanilla armor layer. For example:
+     * <pre>{@code
+     * TransformedItemStack customHelmet = armor.helmetItem();
+     * if (customHelmet != null) {
+     *     // Render the original item stack with its custom item model.
+     * }
+     * }</pre>
+     *
+     * @return the custom helmet item, or {@code null} for vanilla armor rendering
+     * @since 3.4.1
+     */
+    default @Nullable TransformedItemStack helmetItem() {
+        return null;
+    }
+
     /**
      * Gets chestplate
      * @return chestplate
diff --git a/core/build.gradle.kts b/core/build.gradle.kts
index 0fefb45f9..2228673f1 100644
--- a/core/build.gradle.kts
+++ b/core/build.gradle.kts
@@ -10,4 +10,6 @@ dependencies {
 
     compileOnly(libs.bundles.core)
     compileOnly(libs.cloud.core)
+
+    testImplementation(libs.bundles.minecraft)
 }
diff --git a/core/src/main/kotlin/kr/toxicity/model/manager/ModelManagerImpl.kt b/core/src/main/kotlin/kr/toxicity/model/manager/ModelManagerImpl.kt
index 9affed466..8ebd8e828 100644
--- a/core/src/main/kotlin/kr/toxicity/model/manager/ModelManagerImpl.kt
+++ b/core/src/main/kotlin/kr/toxicity/model/manager/ModelManagerImpl.kt
@@ -10,6 +10,11 @@ package kr.toxicity.model.manager
 import com.google.gson.JsonArray
 import com.google.gson.JsonObject
 import kr.toxicity.model.api.bone.BoneItemMapper
+import kr.toxicity.model.api.bone.BoneName
+import kr.toxicity.model.api.bone.BoneRenderContext
+import kr.toxicity.model.api.bone.BoneTag
+import kr.toxicity.model.api.bone.BoneTags
+import kr.toxicity.model.api.data.Float3
 import kr.toxicity.model.api.data.ModelAsset
 import kr.toxicity.model.api.data.blueprint.BlueprintElement
 import kr.toxicity.model.api.data.blueprint.BlueprintJson
@@ -19,12 +24,17 @@ import kr.toxicity.model.api.data.renderer.RendererGroup
 import kr.toxicity.model.api.event.ModelAssetsEvent
 import kr.toxicity.model.api.event.ModelImportedEvent
 import kr.toxicity.model.api.manager.ModelManager
+import kr.toxicity.model.api.nms.Profiled
 import kr.toxicity.model.api.pack.PackBuilder
 import kr.toxicity.model.api.pack.PackZipper
+import kr.toxicity.model.api.platform.PlatformItemTransform
 import kr.toxicity.model.api.platform.PlatformNamespace
+import kr.toxicity.model.api.util.TransformedItemStack
 import kr.toxicity.model.util.*
 import net.kyori.adventure.text.format.NamedTextColor.*
 import java.io.File
+import java.nio.charset.StandardCharsets
+import java.util.UUID
 import java.util.concurrent.ConcurrentHashMap
 import kotlin.io.path.extension
 
@@ -36,6 +46,24 @@ object ModelManagerImpl : ModelManager, GlobalManager {
     private val playerModelView = playerModelMap.toImmutableView()
     private val modelExtensions = setOf("bbmodel", "ajmodel")
 
+    private val customHeadItemMapper = object : BoneItemMapper {
+        override fun apply(
+            context: BoneRenderContext,
+            transformedItemStack: TransformedItemStack
+        ): TransformedItemStack = (context.source() as? Profiled)
+            ?.armors()
+            ?.helmetItem()
+            ?: TransformedItemStack.empty()
+
+        override fun transform(): PlatformItemTransform = PlatformItemTransform.HEAD
+    }
+
+    private val customHeadItemTag = object : BoneTag {
+        override fun name(): String = INTERNAL_HEAD_ITEM_NAME
+        override fun itemMapper(): BoneItemMapper = customHeadItemMapper
+        override fun tags(): List<String> = emptyList()
+    }
+
     private fun importModels(
         type: ModelRenderer.Type,
         pipeline: ReloadPipeline,
@@ -231,15 +259,45 @@ object ModelManagerImpl : ModelManager, GlobalManager {
             fun <T> Collection<BlueprintElement>.toBoneMap(mapper: (BlueprintElement.Bone) -> T) = filterIsInstance<BlueprintElement.Bone>().let { bone ->
                 bone.associateTo(sequencedAddressingMapOf(bone.size)) { it.name() to mapper(it) }
             }.toImmutableView()
+
+            fun BlueprintElement.Bone.customHeadItemRenderer(
+                existingChildren: Map<BoneName, RendererGroup>
+            ): RendererGroup {
+                val baseName = "$INTERNAL_HEAD_ITEM_NAME:${uuid()}"
+                var rawName = baseName
+                var collision = 0
+                while (existingChildren.keys.any { it.rawName() == rawName }) {
+                    rawName = "$baseName:${++collision}"
+                }
+                val internalBone = BlueprintElement.Group(
+                    UUID.nameUUIDFromBytes(rawName.toByteArray(StandardCharsets.UTF_8)),
+                    BoneName(setOf(customHeadItemTag), rawName, rawName),
+                    origin().invertXZ(),
+                    Float3.ZERO,
+                    emptyList(),
+                    true
+                )
+                return RendererGroup(1.0F, null, internalBone, emptySequencedMap(), null)
+            }
+
             fun BlueprintElement.Bone.parse(): RendererGroup {
-                if (this !is BlueprintElement.Group) return RendererGroup(1.0F, null, this, emptySequencedMap(), null)
+                val childRenderers = if (this is BlueprintElement.Group) {
+                    children.toBoneMap { it.parse() }
+                } else emptySequencedMap()
+                val renderedChildren = if (type == ModelRenderer.Type.PLAYER && name().tagged(BoneTags.PLAYER_HEAD)) {
+                    sequencedAddressingMapOf<BoneName, RendererGroup>(childRenderers.size + 1).apply {
+                        putAll(childRenderers)
+                        customHeadItemRenderer(childRenderers).let { put(it.name(), it) }
+                    }.toImmutableView()
+                } else childRenderers
+                if (this !is BlueprintElement.Group) return RendererGroup(1.0F, null, this, renderedChildren, null)
                 return RendererGroup(
                     scale(),
                     if (name.toItemMapper() !== BoneItemMapper.EMPTY) null else builder(this)?.let { itemNamespace ->
                         CONFIG.item().get().itemModel(PlatformNamespace(CONFIG.namespace(), itemNamespace))
                     },
                     this,
-                    children.toBoneMap { it.parse() },
+                    renderedChildren,
                     hitBox(),
                 )
             }
@@ -267,4 +325,6 @@ object ModelManagerImpl : ModelManager, GlobalManager {
     override fun limb(name: String): ModelRenderer? = playerModelView[name]
     override fun limbs(): Collection<ModelRenderer> = playerModelView.values
     override fun limbKeys(): Set<String> = playerModelView.keys
+
+    private const val INTERNAL_HEAD_ITEM_NAME = "bettermodel:internal_player_head_item"
 }
diff --git a/core/src/main/kotlin/kr/toxicity/model/manager/SkinManagerImpl.kt b/core/src/main/kotlin/kr/toxicity/model/manager/SkinManagerImpl.kt
index 05fe1fb1e..caf111c02 100644
--- a/core/src/main/kotlin/kr/toxicity/model/manager/SkinManagerImpl.kt
+++ b/core/src/main/kotlin/kr/toxicity/model/manager/SkinManagerImpl.kt
@@ -793,7 +793,10 @@ object SkinManagerImpl : SkinManager, GlobalManager {
             capeImage?.let { CAPE.asModelData(it).asItem() }
         )
         override fun profile(): ModelProfile = profile
-        override fun head(armor: PlayerArmor): TransformedItemStack = head.asItem(ArmorResource.HELMET, armor.helmet())
+        override fun head(armor: PlayerArmor): TransformedItemStack = head.asItem(
+            ArmorResource.HELMET,
+            armor.helmet().takeIf { armor.helmetItem() == null }
+        )
         override fun hip(armor: PlayerArmor): TransformedItemStack = hip.asItem(ArmorResource.HIP, armor.leggings())
         override fun waist(armor: PlayerArmor): TransformedItemStack = waist.asItem(ArmorResource.WAIST, armor.chestplate())
         override fun chest(armor: PlayerArmor): TransformedItemStack = chest.asItem(ArmorResource.CHEST, armor.chestplate())
diff --git a/core/src/test/kotlin/kr/toxicity/model/manager/PlayerModelRendererTest.kt b/core/src/test/kotlin/kr/toxicity/model/manager/PlayerModelRendererTest.kt
new file mode 100644
index 000000000..5f2e6d8ea
--- /dev/null
+++ b/core/src/test/kotlin/kr/toxicity/model/manager/PlayerModelRendererTest.kt
@@ -0,0 +1,238 @@
+/*
+ * This source file is part of BetterModel.
+ * Copyright (c) 2026 toxicity188
+ * Licensed under the MIT License.
+ * See LICENSE.md file for full license text.
+ */
+
+package kr.toxicity.model.manager
+
+import kr.toxicity.model.api.BetterModel
+import kr.toxicity.model.api.BetterModelPlatform
+import kr.toxicity.model.api.armor.ArmorItem
+import kr.toxicity.model.api.armor.PlayerArmor
+import kr.toxicity.model.api.bone.BoneName
+import kr.toxicity.model.api.bone.BoneRenderContext
+import kr.toxicity.model.api.bone.BoneTag
+import kr.toxicity.model.api.data.Float3
+import kr.toxicity.model.api.data.blueprint.BlueprintElement
+import kr.toxicity.model.api.data.blueprint.ModelBlueprint
+import kr.toxicity.model.api.data.raw.ModelResolution
+import kr.toxicity.model.api.data.renderer.ModelRenderer
+import kr.toxicity.model.api.data.renderer.RenderSource
+import kr.toxicity.model.api.data.renderer.RendererGroup
+import kr.toxicity.model.api.entity.BasePlayer
+import kr.toxicity.model.api.platform.PlatformAdapter
+import kr.toxicity.model.api.platform.PlatformItemStack
+import kr.toxicity.model.api.platform.PlatformItemTransform
+import kr.toxicity.model.api.platform.PlatformNamespace
+import kr.toxicity.model.api.skin.SkinData
+import kr.toxicity.model.api.util.TransformedItemStack
+import java.lang.reflect.Method
+import java.lang.reflect.Proxy
+import java.util.UUID
+import sun.misc.Unsafe
+import kotlin.test.AfterTest
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotNull
+import kotlin.test.assertNull
+import kotlin.test.assertSame
+import kotlin.test.assertTrue
+
+/**
+ * Player-renderer regression coverage for BetterModel issue #410.
+ */
+class PlayerModelRendererTest {
+
+    private var previousPlatform: Any? = null
+
+    @BeforeTest
+    fun installPlatform() {
+        platformField().run {
+            previousPlatform = get(null)
+            set(null, platform())
+        }
+    }
+
+    @AfterTest
+    fun restorePlatform() {
+        platformField().set(null, previousPlatform)
+    }
+
+    @Test
+    fun `player head receives an internal custom-item child`() {
+        val first = playerRenderer()
+        val second = playerRenderer()
+        val firstHead = assertNotNull(first.groupByTree(headName()))
+        val secondHead = assertNotNull(second.groupByTree(headName()))
+        val firstHeadItem = assertNotNull(firstHead.customHeadItem())
+        val secondHeadItem = assertNotNull(secondHead.customHeadItem())
+
+        assertNotNull(firstHead.children[authoredChildName()])
+        assertNotNull(firstHead.children[collidingChildName()])
+        assertEquals(firstHead.position, firstHeadItem.position)
+        assertTrue(firstHeadItem.parent.visibility())
+        assertEquals(firstHeadItem.uuid(), secondHeadItem.uuid())
+        assertEquals(firstHeadItem.name(), secondHeadItem.name())
+        assertTrue(firstHeadItem.name() != collidingChildName())
+        assertTrue(BoneName.of(firstHeadItem.name().rawName()).tags().isEmpty())
+        assertNull(BoneTag.REGISTRY.byTagNameOrNull("phi"))
+    }
+
+    @Test
+    fun `internal custom-item child renders the preserved helmet with head transform`() {
+        val customItem = TransformedItemStack.of(TestItem(false))
+        val mapper = assertNotNull(
+            assertNotNull(playerRenderer().groupByTree(headName())).customHeadItem()
+        ).itemMapper
+
+        val mapped = mapper.apply(context(armor(customItem)), TransformedItemStack.empty())
+
+        assertSame(customItem, mapped)
+        assertEquals(PlatformItemTransform.HEAD, mapper.transform())
+    }
+
+    @Test
+    fun `internal custom-item child renders air when helmet is not customized`() {
+        val mapper = assertNotNull(
+            assertNotNull(playerRenderer().groupByTree(headName())).customHeadItem()
+        ).itemMapper
+
+        val mapped = mapper.apply(context(armor(null)), TransformedItemStack.empty())
+
+        assertTrue(mapped.isAir)
+    }
+
+    @Test
+    fun `general models do not receive the internal player child`() {
+        val head = assertNotNull(toRenderer(ModelRenderer.Type.GENERAL).groupByTree(headName()))
+
+        assertNull(head.customHeadItem())
+    }
+
+    private fun playerRenderer() = toRenderer(ModelRenderer.Type.PLAYER)
+
+    private fun toRenderer(type: ModelRenderer.Type): ModelRenderer {
+        val pipelineClass = ModelManagerImpl::class.java.declaredClasses.single {
+            it.simpleName == "ModelPipeline"
+        }
+        val converter = pipelineClass.declaredMethods.single {
+            it.name == "toRenderer" &&
+                it.parameterTypes.firstOrNull() == ModelBlueprint::class.java
+        }
+        converter.isAccessible = true
+        val itemBuilder: (BlueprintElement.Group) -> String? = { null }
+        val pipeline = UNSAFE.allocateInstance(pipelineClass)
+        return converter.invoke(pipeline, blueprint(), type, itemBuilder) as ModelRenderer
+    }
+
+    private fun blueprint(): ModelBlueprint {
+        val authoredChild = BlueprintElement.Locator(
+            AUTHORED_CHILD_UUID,
+            authoredChildName(),
+            Float3(4F, 24F, -2F)
+        )
+        val collidingChild = BlueprintElement.Locator(
+            COLLIDING_CHILD_UUID,
+            collidingChildName(),
+            Float3(4F, 24F, -2F)
+        )
+        val head = BlueprintElement.Group(
+            HEAD_UUID,
+            headName(),
+            Float3(4F, 24F, -2F),
+            Float3.ZERO,
+            listOf(authoredChild, collidingChild),
+            true
+        )
+        return ModelBlueprint(
+            "existing_player_rig",
+            ModelResolution(64, 64),
+            emptyList(),
+            listOf(head),
+            emptyMap()
+        )
+    }
+
+    private fun RendererGroup.customHeadItem(): RendererGroup? = children.values.singleOrNull {
+        it.itemMapper.transform() == PlatformItemTransform.HEAD
+    }
+
+    private fun headName() = BoneName.of("ph_head")
+
+    private fun authoredChildName() = BoneName.of("authored_child")
+
+    private fun collidingChildName(): BoneName {
+        val rawName = "bettermodel:internal_player_head_item:$HEAD_UUID"
+        return BoneName(emptySet(), rawName, rawName)
+    }
+
+    private fun context(armor: PlayerArmor): BoneRenderContext {
+        val player = proxy<BasePlayer> { method, _ ->
+            if (method.name == "armors") armor else defaultValue(method.returnType)
+        }
+        val skin = proxy<SkinData> { method, _ -> defaultValue(method.returnType) }
+        return BoneRenderContext(RenderSource.of(player), skin)
+    }
+
+    private fun armor(helmetItem: TransformedItemStack?) = object : PlayerArmor {
+        override fun helmet(): ArmorItem? = null
+        override fun helmetItem(): TransformedItemStack? = helmetItem
+        override fun chestplate(): ArmorItem? = null
+        override fun leggings(): ArmorItem? = null
+        override fun boots(): ArmorItem? = null
+    }
+
+    private fun platform(): BetterModelPlatform {
+        val adapter = proxy<PlatformAdapter> { method, _ ->
+            if (method.name == "air") AIR else defaultValue(method.returnType)
+        }
+        return proxy { method, _ ->
+            if (method.name == "adapter") adapter else defaultValue(method.returnType)
+        }
+    }
+
+    private fun platformField() = BetterModel::class.java.getDeclaredField("instance").apply {
+        isAccessible = true
+    }
+
+    private inline fun <reified T> proxy(
+        noinline invocation: (Method, Array<out Any?>?) -> Any?
+    ): T = Proxy.newProxyInstance(
+        T::class.java.classLoader,
+        arrayOf(T::class.java)
+    ) { _, method, arguments -> invocation(method, arguments) } as T
+
+    private fun defaultValue(type: Class<*>): Any? = when {
+        !type.isPrimitive -> null
+        type == Boolean::class.javaPrimitiveType -> false
+        type == Char::class.javaPrimitiveType -> '\u0000'
+        type == Byte::class.javaPrimitiveType -> 0.toByte()
+        type == Short::class.javaPrimitiveType -> 0.toShort()
+        type == Int::class.javaPrimitiveType -> 0
+        type == Long::class.javaPrimitiveType -> 0L
+        type == Float::class.javaPrimitiveType -> 0F
+        type == Double::class.javaPrimitiveType -> 0.0
+        else -> error("Unknown primitive type: $type")
+    }
+
+    private data class TestItem(private val air: Boolean) : PlatformItemStack {
+        override fun isAir(): Boolean = air
+        override fun enchant(enchant: Boolean): PlatformItemStack = this
+        override fun itemModel(namespace: PlatformNamespace?): PlatformItemStack = this
+        public override fun clone(): PlatformItemStack = this
+    }
+
+    private companion object {
+        private val AIR = TestItem(true)
+        private val UNSAFE = Unsafe::class.java.getDeclaredField("theUnsafe").run {
+            isAccessible = true
+            get(null) as Unsafe
+        }
+        private val HEAD_UUID = UUID.fromString("a3172126-8b18-4bee-bfae-410000000001")
+        private val AUTHORED_CHILD_UUID = UUID.fromString("a3172126-8b18-4bee-bfae-410000000002")
+        private val COLLIDING_CHILD_UUID = UUID.fromString("a3172126-8b18-4bee-bfae-410000000003")
+    }
+}
diff --git a/nms/v1_21_R3/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R3/PlayerArmorImpl.kt b/nms/v1_21_R3/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R3/PlayerArmorImpl.kt
index 16424acd2..ef5e4c68a 100644
--- a/nms/v1_21_R3/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R3/PlayerArmorImpl.kt
+++ b/nms/v1_21_R3/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R3/PlayerArmorImpl.kt
@@ -9,6 +9,7 @@ package kr.toxicity.model.bukkit.nms.v1_21_R3
 
 import kr.toxicity.model.api.armor.ArmorItem
 import kr.toxicity.model.api.armor.PlayerArmor
+import kr.toxicity.model.api.util.TransformedItemStack
 import net.minecraft.core.component.DataComponents
 import net.minecraft.world.entity.EquipmentSlot
 import net.minecraft.world.item.component.DyedItemColor
@@ -23,6 +24,10 @@ internal data class PlayerArmorImpl(
         return player.handle.getItemBySlot(EquipmentSlot.HEAD).toArmorItem()
     }
 
+    override fun helmetItem(): TransformedItemStack? {
+        return player.handle.getItemBySlot(EquipmentSlot.HEAD).toCustomItem()
+    }
+
     override fun leggings(): ArmorItem? {
         return player.handle.getItemBySlot(EquipmentSlot.LEGS).toArmorItem()
     }
@@ -44,4 +49,12 @@ internal data class PlayerArmorImpl(
             trim?.material?.value()?.assetName
         )
     }?.orElse(null)
+
+    private fun VanillaItemStack.toCustomItem(): TransformedItemStack? {
+        val defaultComponents = item.components()
+        if (get(DataComponents.ITEM_MODEL) == defaultComponents.get(DataComponents.ITEM_MODEL) &&
+            get(DataComponents.CUSTOM_MODEL_DATA) == defaultComponents.get(DataComponents.CUSTOM_MODEL_DATA)
+        ) return null
+        return TransformedItemStack.of(copy().asBukkit().wrap())
+    }
 }
diff --git a/nms/v1_21_R4/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R4/PlayerArmorImpl.kt b/nms/v1_21_R4/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R4/PlayerArmorImpl.kt
index 328be680f..d29bc0ef2 100644
--- a/nms/v1_21_R4/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R4/PlayerArmorImpl.kt
+++ b/nms/v1_21_R4/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R4/PlayerArmorImpl.kt
@@ -9,6 +9,7 @@ package kr.toxicity.model.bukkit.nms.v1_21_R4
 
 import kr.toxicity.model.api.armor.ArmorItem
 import kr.toxicity.model.api.armor.PlayerArmor
+import kr.toxicity.model.api.util.TransformedItemStack
 import net.minecraft.core.component.DataComponents
 import net.minecraft.world.entity.EquipmentSlot
 import net.minecraft.world.item.component.DyedItemColor
@@ -23,6 +24,10 @@ internal data class PlayerArmorImpl(
         return player.handle.getItemBySlot(EquipmentSlot.HEAD).toArmorItem()
     }
 
+    override fun helmetItem(): TransformedItemStack? {
+        return player.handle.getItemBySlot(EquipmentSlot.HEAD).toCustomItem()
+    }
+
     override fun leggings(): ArmorItem? {
         return player.handle.getItemBySlot(EquipmentSlot.LEGS).toArmorItem()
     }
@@ -44,4 +49,12 @@ internal data class PlayerArmorImpl(
             trim?.material?.value()?.assets?.base?.suffix
         )
     }?.orElse(null)
+
+    private fun VanillaItemStack.toCustomItem(): TransformedItemStack? {
+        val defaultComponents = item.components()
+        if (get(DataComponents.ITEM_MODEL) == defaultComponents.get(DataComponents.ITEM_MODEL) &&
+            get(DataComponents.CUSTOM_MODEL_DATA) == defaultComponents.get(DataComponents.CUSTOM_MODEL_DATA)
+        ) return null
+        return TransformedItemStack.of(copy().asBukkit().wrap())
+    }
 }
diff --git a/nms/v1_21_R5/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R5/PlayerArmorImpl.kt b/nms/v1_21_R5/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R5/PlayerArmorImpl.kt
index 0c3933f44..0a6ceabee 100644
--- a/nms/v1_21_R5/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R5/PlayerArmorImpl.kt
+++ b/nms/v1_21_R5/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R5/PlayerArmorImpl.kt
@@ -9,6 +9,7 @@ package kr.toxicity.model.bukkit.nms.v1_21_R5
 
 import kr.toxicity.model.api.armor.ArmorItem
 import kr.toxicity.model.api.armor.PlayerArmor
+import kr.toxicity.model.api.util.TransformedItemStack
 import net.minecraft.core.component.DataComponents
 import net.minecraft.world.entity.EquipmentSlot
 import net.minecraft.world.item.component.DyedItemColor
@@ -23,6 +24,10 @@ internal data class PlayerArmorImpl(
         return player.handle.getItemBySlot(EquipmentSlot.HEAD).toArmorItem()
     }
 
+    override fun helmetItem(): TransformedItemStack? {
+        return player.handle.getItemBySlot(EquipmentSlot.HEAD).toCustomItem()
+    }
+
     override fun leggings(): ArmorItem? {
         return player.handle.getItemBySlot(EquipmentSlot.LEGS).toArmorItem()
     }
@@ -44,4 +49,12 @@ internal data class PlayerArmorImpl(
             trim?.material?.value()?.assets?.base?.suffix
         )
     }?.orElse(null)
+
+    private fun VanillaItemStack.toCustomItem(): TransformedItemStack? {
+        val defaultComponents = item.components()
+        if (get(DataComponents.ITEM_MODEL) == defaultComponents.get(DataComponents.ITEM_MODEL) &&
+            get(DataComponents.CUSTOM_MODEL_DATA) == defaultComponents.get(DataComponents.CUSTOM_MODEL_DATA)
+        ) return null
+        return TransformedItemStack.of(copy().asBukkit().wrap())
+    }
 }
diff --git a/nms/v1_21_R6/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R6/PlayerArmorImpl.kt b/nms/v1_21_R6/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R6/PlayerArmorImpl.kt
index f859db910..c3a21f855 100644
--- a/nms/v1_21_R6/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R6/PlayerArmorImpl.kt
+++ b/nms/v1_21_R6/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R6/PlayerArmorImpl.kt
@@ -9,6 +9,7 @@ package kr.toxicity.model.bukkit.nms.v1_21_R6
 
 import kr.toxicity.model.api.armor.ArmorItem
 import kr.toxicity.model.api.armor.PlayerArmor
+import kr.toxicity.model.api.util.TransformedItemStack
 import net.minecraft.core.component.DataComponents
 import net.minecraft.world.entity.EquipmentSlot
 import net.minecraft.world.item.component.DyedItemColor
@@ -23,6 +24,10 @@ internal data class PlayerArmorImpl(
         return player.handle.getItemBySlot(EquipmentSlot.HEAD).toArmorItem()
     }
 
+    override fun helmetItem(): TransformedItemStack? {
+        return player.handle.getItemBySlot(EquipmentSlot.HEAD).toCustomItem()
+    }
+
     override fun leggings(): ArmorItem? {
         return player.handle.getItemBySlot(EquipmentSlot.LEGS).toArmorItem()
     }
@@ -44,4 +49,12 @@ internal data class PlayerArmorImpl(
             trim?.material?.value()?.assets?.base?.suffix
         )
     }?.orElse(null)
+
+    private fun VanillaItemStack.toCustomItem(): TransformedItemStack? {
+        val defaultComponents = item.components()
+        if (get(DataComponents.ITEM_MODEL) == defaultComponents.get(DataComponents.ITEM_MODEL) &&
+            get(DataComponents.CUSTOM_MODEL_DATA) == defaultComponents.get(DataComponents.CUSTOM_MODEL_DATA)
+        ) return null
+        return TransformedItemStack.of(copy().asBukkit().wrap())
+    }
 }
diff --git a/nms/v1_21_R7/build.gradle.kts b/nms/v1_21_R7/build.gradle.kts
index d1245d7af..107a4dcd3 100644
--- a/nms/v1_21_R7/build.gradle.kts
+++ b/nms/v1_21_R7/build.gradle.kts
@@ -6,6 +6,8 @@ plugins {
 
 dependencies {
     paperweight.paperDevBundle("1.21.11-R0.1-SNAPSHOT")
+    testImplementation(project(":bettermodel-api"))
+    testImplementation(project(":bettermodel-api:bettermodel-bukkit-api"))
 }
 
 tasks {
diff --git a/nms/v1_21_R7/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R7/PlayerArmorImpl.kt b/nms/v1_21_R7/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R7/PlayerArmorImpl.kt
index 02cf31564..5b8fe2541 100644
--- a/nms/v1_21_R7/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R7/PlayerArmorImpl.kt
+++ b/nms/v1_21_R7/src/main/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R7/PlayerArmorImpl.kt
@@ -9,6 +9,7 @@ package kr.toxicity.model.bukkit.nms.v1_21_R7
 
 import kr.toxicity.model.api.armor.ArmorItem
 import kr.toxicity.model.api.armor.PlayerArmor
+import kr.toxicity.model.api.util.TransformedItemStack
 import net.minecraft.core.component.DataComponents
 import net.minecraft.world.entity.EquipmentSlot
 import net.minecraft.world.item.component.DyedItemColor
@@ -23,6 +24,10 @@ internal data class PlayerArmorImpl(
         return player.handle.getItemBySlot(EquipmentSlot.HEAD).toArmorItem()
     }
 
+    override fun helmetItem(): TransformedItemStack? {
+        return player.handle.getItemBySlot(EquipmentSlot.HEAD).toCustomItem()
+    }
+
     override fun leggings(): ArmorItem? {
         return player.handle.getItemBySlot(EquipmentSlot.LEGS).toArmorItem()
     }
@@ -44,4 +49,12 @@ internal data class PlayerArmorImpl(
             trim?.material?.value()?.assets?.base?.suffix
         )
     }?.orElse(null)
+
+    private fun VanillaItemStack.toCustomItem(): TransformedItemStack? {
+        val defaultComponents = item.components()
+        if (get(DataComponents.ITEM_MODEL) == defaultComponents.get(DataComponents.ITEM_MODEL) &&
+            get(DataComponents.CUSTOM_MODEL_DATA) == defaultComponents.get(DataComponents.CUSTOM_MODEL_DATA)
+        ) return null
+        return TransformedItemStack.of(copy().asBukkit().wrap())
+    }
 }
diff --git a/nms/v1_21_R7/src/test/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R7/PlayerArmorImplTest.kt b/nms/v1_21_R7/src/test/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R7/PlayerArmorImplTest.kt
new file mode 100644
index 000000000..c05690c1b
--- /dev/null
+++ b/nms/v1_21_R7/src/test/kotlin/kr/toxicity/model/bukkit/nms/v1_21_R7/PlayerArmorImplTest.kt
@@ -0,0 +1,96 @@
+/*
+ * This source file is part of BetterModel.
+ * Copyright (c) 2026 toxicity188
+ * Licensed under the MIT License.
+ * See LICENSE.md file for full license text.
+ */
+
+package kr.toxicity.model.bukkit.nms.v1_21_R7
+
+import kr.toxicity.model.api.bukkit.platform.BukkitItemStack
+import kr.toxicity.model.api.util.TransformedItemStack
+import net.minecraft.SharedConstants
+import net.minecraft.core.component.DataComponents
+import net.minecraft.resources.Identifier
+import net.minecraft.server.Bootstrap
+import net.minecraft.world.item.ItemStack
+import net.minecraft.world.item.Items
+import net.minecraft.world.item.component.CustomModelData
+import org.bukkit.craftbukkit.inventory.CraftItemStack
+import sun.misc.Unsafe
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotNull
+import kotlin.test.assertNull
+
+/**
+ * Acceptance criteria from BetterModel issue #410:
+ * 1. A head item with an item-model component is preserved as a separate custom head item when
+ *    BetterModel converts it for player-emote rendering.
+ * 2. A head item with custom-model-data is preserved as a separate custom head item when BetterModel
+ *    converts it for player-emote rendering.
+ */
+class PlayerArmorImplTest {
+
+    @BeforeTest
+    fun bootstrapRegistries() {
+        SharedConstants.tryDetectVersion()
+        Bootstrap.bootStrap()
+    }
+
+    @Test
+    fun `preserves item model when converting head equipment`() {
+        val plain = Items.IRON_HELMET.defaultInstance
+        val itemModel = Identifier.parse("bettermodel:issue_410_hat")
+        val customized = plain.copy().apply {
+            set(DataComponents.ITEM_MODEL, itemModel)
+        }
+
+        assertEquals(itemModel, customized.get(DataComponents.ITEM_MODEL))
+        assertNull(convertCustomItem(plain))
+        val converted = assertNotNull(convertCustomItem(customized))
+        assertEquals(itemModel, unwrap(converted).get(DataComponents.ITEM_MODEL))
+    }
+
+    @Test
+    fun `preserves custom model data when converting head equipment`() {
+        val plain = Items.IRON_HELMET.defaultInstance
+        val customModelData = CustomModelData(
+            listOf(410F),
+            emptyList<Boolean>(),
+            emptyList<String>(),
+            emptyList<Int>()
+        )
+        val customized = plain.copy().apply {
+            set(DataComponents.CUSTOM_MODEL_DATA, customModelData)
+        }
+
+        assertEquals(customModelData, customized.get(DataComponents.CUSTOM_MODEL_DATA))
+        assertNull(convertCustomItem(plain))
+        val converted = assertNotNull(convertCustomItem(customized))
+        assertEquals(customModelData, unwrap(converted).get(DataComponents.CUSTOM_MODEL_DATA))
+    }
+
+    private fun convertCustomItem(itemStack: ItemStack): TransformedItemStack? {
+        val converter = PlayerArmorImpl::class.java.declaredMethods.singleOrNull {
+            it.parameterTypes.contentEquals(arrayOf(ItemStack::class.java)) &&
+                it.returnType == TransformedItemStack::class.java
+        }
+        assertNotNull(converter, "PlayerArmorImpl must preserve custom head-item model data")
+        converter.isAccessible = true
+        return converter.invoke(converterOwner, itemStack) as TransformedItemStack?
+    }
+
+    private fun unwrap(itemStack: TransformedItemStack): ItemStack = CraftItemStack.asNMSCopy(
+        (itemStack.itemStack as BukkitItemStack).source()
+    )
+
+    private companion object {
+        private val unsafe = Unsafe::class.java.getDeclaredField("theUnsafe").run {
+            isAccessible = true
+            get(null) as Unsafe
+        }
+        private val converterOwner = unsafe.allocateInstance(PlayerArmorImpl::class.java)
+    }
+}
diff --git a/nms/v26_R1/src/main/kotlin/kr/toxicity/model/bukkit/nms/v26_R1/PlayerArmorImpl.kt b/nms/v26_R1/src/main/kotlin/kr/toxicity/model/bukkit/nms/v26_R1/PlayerArmorImpl.kt
index 6bec07d8f..f3481fdd5 100644
--- a/nms/v26_R1/src/main/kotlin/kr/toxicity/model/bukkit/nms/v26_R1/PlayerArmorImpl.kt
+++ b/nms/v26_R1/src/main/kotlin/kr/toxicity/model/bukkit/nms/v26_R1/PlayerArmorImpl.kt
@@ -9,6 +9,7 @@ package kr.toxicity.model.bukkit.nms.v26_R1
 
 import kr.toxicity.model.api.armor.ArmorItem
 import kr.toxicity.model.api.armor.PlayerArmor
+import kr.toxicity.model.api.util.TransformedItemStack
 import net.minecraft.core.component.DataComponents
 import net.minecraft.world.entity.EquipmentSlot
 import net.minecraft.world.item.component.DyedItemColor
@@ -23,6 +24,10 @@ internal data class PlayerArmorImpl(
         return player.handle.getItemBySlot(EquipmentSlot.HEAD).toArmorItem()
     }
 
+    override fun helmetItem(): TransformedItemStack? {
+        return player.handle.getItemBySlot(EquipmentSlot.HEAD).toCustomItem()
+    }
+
     override fun leggings(): ArmorItem? {
         return player.handle.getItemBySlot(EquipmentSlot.LEGS).toArmorItem()
     }
@@ -44,4 +49,12 @@ internal data class PlayerArmorImpl(
             trim?.material?.value()?.assets?.base?.suffix
         )
     }?.orElse(null)
+
+    private fun VanillaItemStack.toCustomItem(): TransformedItemStack? {
+        val defaultComponents = item.components()
+        if (get(DataComponents.ITEM_MODEL) == defaultComponents.get(DataComponents.ITEM_MODEL) &&
+            get(DataComponents.CUSTOM_MODEL_DATA) == defaultComponents.get(DataComponents.CUSTOM_MODEL_DATA)
+        ) return null
+        return TransformedItemStack.of(copy().asBukkit().wrap())
+    }
 }
diff --git a/nms/v26_R2/src/main/kotlin/kr/toxicity/model/bukkit/nms/v26_R2/PlayerArmorImpl.kt b/nms/v26_R2/src/main/kotlin/kr/toxicity/model/bukkit/nms/v26_R2/PlayerArmorImpl.kt
index 93869b1ed..c9a7d281e 100644
--- a/nms/v26_R2/src/main/kotlin/kr/toxicity/model/bukkit/nms/v26_R2/PlayerArmorImpl.kt
+++ b/nms/v26_R2/src/main/kotlin/kr/toxicity/model/bukkit/nms/v26_R2/PlayerArmorImpl.kt
@@ -9,6 +9,7 @@ package kr.toxicity.model.bukkit.nms.v26_R2
 
 import kr.toxicity.model.api.armor.ArmorItem
 import kr.toxicity.model.api.armor.PlayerArmor
+import kr.toxicity.model.api.util.TransformedItemStack
 import net.minecraft.core.component.DataComponents
 import net.minecraft.world.entity.EquipmentSlot
 import net.minecraft.world.item.component.DyedItemColor
@@ -23,6 +24,10 @@ internal data class PlayerArmorImpl(
         return player.handle.getItemBySlot(EquipmentSlot.HEAD).toArmorItem()
     }
 
+    override fun helmetItem(): TransformedItemStack? {
+        return player.handle.getItemBySlot(EquipmentSlot.HEAD).toCustomItem()
+    }
+
     override fun leggings(): ArmorItem? {
         return player.handle.getItemBySlot(EquipmentSlot.LEGS).toArmorItem()
     }
@@ -44,4 +49,12 @@ internal data class PlayerArmorImpl(
             trim?.material?.value()?.assets?.base?.suffix
         )
     }?.orElse(null)
+
+    private fun VanillaItemStack.toCustomItem(): TransformedItemStack? {
+        val defaultComponents = item.components()
+        if (get(DataComponents.ITEM_MODEL) == defaultComponents.get(DataComponents.ITEM_MODEL) &&
+            get(DataComponents.CUSTOM_MODEL_DATA) == defaultComponents.get(DataComponents.CUSTOM_MODEL_DATA)
+        ) return null
+        return TransformedItemStack.of(copy().asBukkit().wrap())
+    }
 }
diff --git a/platform/fabric/src/main/kotlin/kr/toxicity/model/impl/fabric/armor/PlayerArmorImpl.kt b/platform/fabric/src/main/kotlin/kr/toxicity/model/impl/fabric/armor/PlayerArmorImpl.kt
index 579be337b..519ad77eb 100644
--- a/platform/fabric/src/main/kotlin/kr/toxicity/model/impl/fabric/armor/PlayerArmorImpl.kt
+++ b/platform/fabric/src/main/kotlin/kr/toxicity/model/impl/fabric/armor/PlayerArmorImpl.kt
@@ -9,6 +9,8 @@ package kr.toxicity.model.impl.fabric.armor
 
 import kr.toxicity.model.api.armor.ArmorItem
 import kr.toxicity.model.api.armor.PlayerArmor
+import kr.toxicity.model.api.util.TransformedItemStack
+import kr.toxicity.model.impl.fabric.wrap
 import net.minecraft.core.component.DataComponents
 import net.minecraft.server.network.ServerPlayerConnection
 import net.minecraft.world.entity.EquipmentSlot
@@ -24,6 +26,8 @@ class PlayerArmorImpl(private val connection: ServerPlayerConnection) : PlayerAr
 
     override fun helmet(): ArmorItem? = player.getItemBySlot(EquipmentSlot.HEAD).toArmorItem()
 
+    override fun helmetItem(): TransformedItemStack? = player.getItemBySlot(EquipmentSlot.HEAD).toCustomItem()
+
     override fun leggings(): ArmorItem? = player.getItemBySlot(EquipmentSlot.LEGS).toArmorItem()
 
     override fun chestplate(): ArmorItem? = player.getItemBySlot(EquipmentSlot.CHEST).toArmorItem()
@@ -45,6 +49,14 @@ class PlayerArmorImpl(private val connection: ServerPlayerConnection) : PlayerAr
         )
     }
 
+    private fun ItemStack.toCustomItem(): TransformedItemStack? {
+        val defaultComponents = item.components()
+        if (get(DataComponents.ITEM_MODEL) == defaultComponents.get(DataComponents.ITEM_MODEL) &&
+            get(DataComponents.CUSTOM_MODEL_DATA) == defaultComponents.get(DataComponents.CUSTOM_MODEL_DATA)
+        ) return null
+        return TransformedItemStack.of(copy().wrap())
+    }
+
     private fun ArmorTrim.getPath() = pattern.value().assetId.path
 
     private fun ArmorTrim.getPalette() = material.value().assets.base.suffix