diff --git a/src/engine/client.h b/src/engine/client.h
index fdc114baa..fb0186a93 100644
--- a/src/engine/client.h
+++ b/src/engine/client.h
@@ -219,7 +219,7 @@ class IClient : public IInterface
 
 	// TODO: Refactor: should redo this a bit i think, too many virtual calls
 	virtual int SnapNumItems(int SnapID) const = 0;
-	virtual void *SnapFindItem(int SnapID, int Type, int ID) const = 0;
+	virtual const void *SnapFindItem(int SnapID, int Type, int ID) const = 0;
 	virtual void *SnapGetItem(int SnapID, int Index, CSnapItem *pItem) const = 0;
 	virtual int SnapItemSize(int SnapID, int Index) const = 0;
 
diff --git a/src/engine/client/client.cpp b/src/engine/client/client.cpp
index 0dfb85816..f3a306109 100644
--- a/src/engine/client/client.cpp
+++ b/src/engine/client/client.cpp
@@ -982,7 +982,7 @@ int CClient::LoadData()
 void *CClient::SnapGetItem(int SnapID, int Index, CSnapItem *pItem) const
 {
 	dbg_assert(SnapID >= 0 && SnapID < NUM_SNAPSHOT_TYPES, "invalid SnapID");
-	CSnapshotItem *pSnapshotItem = m_aapSnapshots[g_Config.m_ClDummy][SnapID]->m_pAltSnap->GetItem(Index);
+	const CSnapshotItem *pSnapshotItem = m_aapSnapshots[g_Config.m_ClDummy][SnapID]->m_pAltSnap->GetItem(Index);
 	pItem->m_DataSize = m_aapSnapshots[g_Config.m_ClDummy][SnapID]->m_pAltSnap->GetItemSize(Index);
 	pItem->m_Type = m_aapSnapshots[g_Config.m_ClDummy][SnapID]->m_pAltSnap->GetItemType(Index);
 	pItem->m_ID = pSnapshotItem->ID();
@@ -995,7 +995,7 @@ int CClient::SnapItemSize(int SnapID, int Index) const
 	return m_aapSnapshots[g_Config.m_ClDummy][SnapID]->m_pAltSnap->GetItemSize(Index);
 }
 
-void *CClient::SnapFindItem(int SnapID, int Type, int ID) const
+const void *CClient::SnapFindItem(int SnapID, int Type, int ID) const
 {
 	if(!m_aapSnapshots[g_Config.m_ClDummy][SnapID])
 		return 0x0;
@@ -2259,10 +2259,10 @@ int CClient::UnpackAndValidateSnapshot(CSnapshot *pFrom, CSnapshot *pTo)
 	int Num = pFrom->NumItems();
 	for(int Index = 0; Index < Num; Index++)
 	{
-		CSnapshotItem *pFromItem = pFrom->GetItem(Index);
+		const CSnapshotItem *pFromItem = pFrom->GetItem(Index);
 		const int FromItemSize = pFrom->GetItemSize(Index);
 		const int ItemType = pFrom->GetItemType(Index);
-		void *pData = pFromItem->Data();
+		const void *pData = pFromItem->Data();
 		Unpacker.Reset(pData, FromItemSize);
 
 		void *pRawObj = pNetObjHandler->SecureUnpackObj(ItemType, &Unpacker);
diff --git a/src/engine/client/client.h b/src/engine/client/client.h
index a877d57b8..2f79ca3d6 100644
--- a/src/engine/client/client.h
+++ b/src/engine/client/client.h
@@ -376,7 +376,7 @@ class CClient : public IClient, public CDemoPlayer::IListener
 	int GetPredictionTime() override;
 	void *SnapGetItem(int SnapID, int Index, CSnapItem *pItem) const override;
 	int SnapItemSize(int SnapID, int Index) const override;
-	void *SnapFindItem(int SnapID, int Type, int ID) const override;
+	const void *SnapFindItem(int SnapID, int Type, int ID) const override;
 	int SnapNumItems(int SnapID) const override;
 	void SnapSetStaticsize(int ItemType, int Size) override;
 
diff --git a/src/engine/shared/snapshot.cpp b/src/engine/shared/snapshot.cpp
index 8f4100314..4dfe1fe00 100644
--- a/src/engine/shared/snapshot.cpp
+++ b/src/engine/shared/snapshot.cpp
@@ -12,9 +12,9 @@
 
 // CSnapshot
 
-CSnapshotItem *CSnapshot::GetItem(int Index) const
+const CSnapshotItem *CSnapshot::GetItem(int Index) const
 {
-	return (CSnapshotItem *)(DataStart() + Offsets()[Index]);
+	return (const CSnapshotItem *)(DataStart() + Offsets()[Index]);
 }
 
 int CSnapshot::GetItemSize(int Index) const
@@ -42,7 +42,7 @@ int CSnapshot::GetExternalItemType(int InternalType) const
 	{
 		return InternalType;
 	}
-	CSnapshotItem *pTypeItem = GetItem(TypeItemIndex);
+	const CSnapshotItem *pTypeItem = GetItem(TypeItemIndex);
 	CUuid Uuid;
 	for(int i = 0; i < (int)sizeof(CUuid) / 4; i++)
 		int_to_bytes_be(&Uuid.m_aData[i * 4], pTypeItem->Data()[i]);
@@ -61,7 +61,7 @@ int CSnapshot::GetItemIndex(int Key) const
 	return -1;
 }
 
-void *CSnapshot::FindItem(int Type, int ID) const
+const void *CSnapshot::FindItem(int Type, int ID) const
 {
 	int InternalType = Type;
 	if(Type >= OFFSET_UUID)
@@ -74,7 +74,7 @@ void *CSnapshot::FindItem(int Type, int ID) const
 		bool Found = false;
 		for(int i = 0; i < m_NumItems; i++)
 		{
-			CSnapshotItem *pItem = GetItem(i);
+			const CSnapshotItem *pItem = GetItem(i);
 			if(pItem->Type() == 0 && pItem->ID() >= OFFSET_UUID_TYPE) // NETOBJTYPE_EX
 			{
 				if(mem_comp(pItem->Data(), aTypeUuidItem, sizeof(CUuid)) == 0)
@@ -100,7 +100,7 @@ unsigned CSnapshot::Crc()
 
 	for(int i = 0; i < m_NumItems; i++)
 	{
-		CSnapshotItem *pItem = GetItem(i);
+		const CSnapshotItem *pItem = GetItem(i);
 		int Size = GetItemSize(i);
 
 		for(int b = 0; b < Size / 4; b++)
@@ -114,7 +114,7 @@ void CSnapshot::DebugDump()
 	dbg_msg("snapshot", "data_size=%d num_items=%d", m_DataSize, m_NumItems);
 	for(int i = 0; i < m_NumItems; i++)
 	{
-		CSnapshotItem *pItem = GetItem(i);
+		const CSnapshotItem *pItem = GetItem(i);
 		int Size = GetItemSize(i);
 		dbg_msg("snapshot", "\ttype=%d id=%d", pItem->Type(), pItem->ID());
 		for(int b = 0; b < Size / 4; b++)
@@ -196,7 +196,7 @@ static int GetItemIndexHashed(int Key, const CItemList *pHashlist)
 	return -1;
 }
 
-int CSnapshotDelta::DiffItem(int *pPast, int *pCurrent, int *pOut, int Size)
+int CSnapshotDelta::DiffItem(const int *pPast, const int *pCurrent, int *pOut, int Size)
 {
 	int Needed = 0;
 	while(Size)
@@ -212,7 +212,7 @@ int CSnapshotDelta::DiffItem(int *pPast, int *pCurrent, int *pOut, int Size)
 	return Needed;
 }
 
-void CSnapshotDelta::UndiffItem(int *pPast, int *pDiff, int *pOut, int Size, int *pDataRate)
+void CSnapshotDelta::UndiffItem(const int *pPast, int *pDiff, int *pOut, int Size, int *pDataRate)
 {
 	while(Size)
 	{
@@ -304,7 +304,7 @@ int CSnapshotDelta::CreateDelta(CSnapshot *pFrom, CSnapshot *pTo, void *pDstData
 	{
 		// do delta
 		const int ItemSize = pTo->GetItemSize(i); // O(1) .. O(n)
-		CSnapshotItem *pCurItem = pTo->GetItem(i); // O(1) .. O(n)
+		const CSnapshotItem *pCurItem = pTo->GetItem(i); // O(1) .. O(n)
 		const int PastIndex = aPastIndices[i];
 		const bool IncludeSize = pCurItem->Type() >= MAX_NETOBJSIZES || !m_aItemSizes[pCurItem->Type()];
 
@@ -312,7 +312,7 @@ int CSnapshotDelta::CreateDelta(CSnapshot *pFrom, CSnapshot *pTo, void *pDstData
 		{
 			int *pItemDataDst = pData + 3;
 
-			CSnapshotItem *pPastItem = pFrom->GetItem(PastIndex);
+			const CSnapshotItem *pPastItem = pFrom->GetItem(PastIndex);
 
 			if(!IncludeSize)
 				pItemDataDst = pData + 2;
@@ -373,7 +373,7 @@ int CSnapshotDelta::UnpackDelta(CSnapshot *pFrom, CSnapshot *pTo, const void *pS
 	// copy all non deleted stuff
 	for(int i = 0; i < pFrom->NumItems(); i++)
 	{
-		CSnapshotItem *pFromItem = pFrom->GetItem(i);
+		const CSnapshotItem *pFromItem = pFrom->GetItem(i);
 		const int ItemSize = pFrom->GetItemSize(i);
 		bool Keep = true;
 		for(int d = 0; d < pDelta->m_NumDeletedItems; d++)
diff --git a/src/engine/shared/snapshot.h b/src/engine/shared/snapshot.h
index 1b8f96781..bb126a136 100644
--- a/src/engine/shared/snapshot.h
+++ b/src/engine/shared/snapshot.h
@@ -10,10 +10,14 @@
 
 class CSnapshotItem
 {
+	friend class CSnapshotBuilder;
+
+	int *Data() { return (int *)(this + 1); }
+
 public:
 	int m_TypeAndID;
 
-	int *Data() { return (int *)(this + 1); }
+	const int *Data() const { return (int *)(this + 1); }
 	int Type() const { return m_TypeAndID >> 16; }
 	int ID() const { return m_TypeAndID & 0xffff; }
 	int Key() const { return m_TypeAndID; }
@@ -48,12 +52,12 @@ class CSnapshot
 		m_NumItems = 0;
 	}
 	int NumItems() const { return m_NumItems; }
-	CSnapshotItem *GetItem(int Index) const;
+	const CSnapshotItem *GetItem(int Index) const;
 	int GetItemSize(int Index) const;
 	int GetItemIndex(int Key) const;
 	int GetItemType(int Index) const;
 	int GetExternalItemType(int InternalType) const;
-	void *FindItem(int Type, int ID) const;
+	const void *FindItem(int Type, int ID) const;
 
 	unsigned Crc();
 	void DebugDump();
@@ -84,10 +88,10 @@ class CSnapshotDelta
 	int m_aSnapshotDataUpdates[CSnapshot::MAX_TYPE + 1];
 	CData m_Empty;
 
-	static void UndiffItem(int *pPast, int *pDiff, int *pOut, int Size, int *pDataRate);
+	static void UndiffItem(const int *pPast, int *pDiff, int *pOut, int Size, int *pDataRate);
 
 public:
-	static int DiffItem(int *pPast, int *pCurrent, int *pOut, int Size);
+	static int DiffItem(const int *pPast, const int *pCurrent, int *pOut, int Size);
 	CSnapshotDelta();
 	CSnapshotDelta(const CSnapshotDelta &Old);
 	int GetDataRate(int Index) const { return m_aSnapshotDataRate[Index]; }
diff --git a/src/game/client/projectile_data.cpp b/src/game/client/projectile_data.cpp
index edf80d6b1..1922e57a7 100644
--- a/src/game/client/projectile_data.cpp
+++ b/src/game/client/projectile_data.cpp
@@ -67,7 +67,7 @@ void SnapshotRemoveExtraProjectileInfo(unsigned char *pData)
 	CSnapshot *pSnap = (CSnapshot *)pData;
 	for(int Index = 0; Index < pSnap->NumItems(); Index++)
 	{
-		CSnapshotItem *pItem = pSnap->GetItem(Index);
+		const CSnapshotItem *pItem = pSnap->GetItem(Index);
 		if(pItem->Type() == NETOBJTYPE_PROJECTILE)
 		{
 			CNetObj_Projectile *pProj = (CNetObj_Projectile *)((void *)pItem->Data());