diff --git a/src/Ledger.h b/src/Ledger.h
index d059f01581..7e2ebb9782 100644
--- a/src/Ledger.h
+++ b/src/Ledger.h
@@ -140,9 +140,8 @@ public:
 	boost::posix_time::ptime getCloseTime() const;
 
 	// low level functions
-	SHAMap::pointer peekTransactionMap() { return mTransactionMap; }
-	SHAMap::pointer peekAccountStateMap() { return mAccountStateMap; }
-	Ledger::pointer snapShot(bool isMutable);
+	SHAMap::ref peekTransactionMap() { return mTransactionMap; }
+	SHAMap::ref peekAccountStateMap() { return mAccountStateMap; }
 
 	// ledger sync functions
 	void setAcquiring(void);
diff --git a/src/SHAMap.h b/src/SHAMap.h
index e7f5046d5c..c239bad307 100644
--- a/src/SHAMap.h
+++ b/src/SHAMap.h
@@ -23,10 +23,6 @@ class SHAMap;
 
 class SHAMapNode
 { // Identifies a node in a SHA256 hash
-public:
-	typedef boost::shared_ptr<SHAMapNode> 			pointer;
-	typedef const boost::shared_ptr<SHAMapNode>&	ref;
-
 private:
 	static uint256 smMasks[65]; // AND with hash to get node id
 
@@ -84,7 +80,8 @@ inline std::ostream& operator<<(std::ostream& out, const SHAMapNode& node) { ret
 class SHAMapItem
 { // an item stored in a SHAMap
 public:
-	typedef boost::shared_ptr<SHAMapItem> pointer;
+	typedef boost::shared_ptr<SHAMapItem>			pointer;
+	typedef const boost::shared_ptr<SHAMapItem>&	ref;
 
 private:
 	uint256 mTag;
@@ -136,7 +133,8 @@ class SHAMapTreeNode : public SHAMapNode
 	friend class SHAMap;
 
 public:
-	typedef boost::shared_ptr<SHAMapTreeNode> pointer;
+	typedef boost::shared_ptr<SHAMapTreeNode>			pointer;
+	typedef const boost::shared_ptr<SHAMapTreeNode>&	ref;
 
 	enum TNType
 	{
@@ -163,7 +161,7 @@ private:
 public:
 	SHAMapTreeNode(uint32 seq, const SHAMapNode& nodeID); // empty node
 	SHAMapTreeNode(const SHAMapTreeNode& node, uint32 seq); // copy node from older tree
-	SHAMapTreeNode(const SHAMapNode& nodeID, const SHAMapItem::pointer& item, TNType type, uint32 seq);
+	SHAMapTreeNode(const SHAMapNode& nodeID, SHAMapItem::ref item, TNType type, uint32 seq);
 
 	// raw node functions
 	SHAMapTreeNode(const SHAMapNode& id, const std::vector<unsigned char>& data, uint32 seq, SHANodeFormat format);
@@ -200,7 +198,7 @@ public:
 
 	// item node function
 	bool hasItem() const { return !!mItem; }
-	SHAMapItem::pointer peekItem() { return mItem; }
+	SHAMapItem::ref peekItem() { return mItem; }
 	SHAMapItem::pointer getItem() const;
 	bool setItem(const SHAMapItem::pointer& i, TNType type);
 	const uint256& getTag() const { return mItem->getTag(); }
@@ -292,7 +290,7 @@ protected:
 	SHAMapItem::pointer onlyBelow(SHAMapTreeNode*);
 	void eraseChildren(SHAMapTreeNode::pointer);
 
-	bool walkBranch(SHAMapTreeNode* node, SHAMapItem::pointer otherMapItem, bool isFirstMap,
+	bool walkBranch(SHAMapTreeNode* node, SHAMapItem::ref otherMapItem, bool isFirstMap,
 	    SHAMapDiff& differences, int& maxCount);
 
 public:
@@ -321,8 +319,8 @@ public:
 	uint256 getHash()			{ return root->getNodeHash(); }
 
 	// save a copy if you have a temporary anyway
-	bool updateGiveItem(const SHAMapItem::pointer&, bool isTransaction, bool hasMeta);
-	bool addGiveItem(const SHAMapItem::pointer&, bool isTransaction, bool hasMeta);
+	bool updateGiveItem(SHAMapItem::ref, bool isTransaction, bool hasMeta);
+	bool addGiveItem(SHAMapItem::ref, bool isTransaction, bool hasMeta);
 
 	// save a copy if you only need a temporary
 	SHAMapItem::pointer peekItem(const uint256& id);
diff --git a/src/SHAMapDiff.cpp b/src/SHAMapDiff.cpp
index 3f5adb3e0d..fa1ae6a642 100644
--- a/src/SHAMapDiff.cpp
+++ b/src/SHAMapDiff.cpp
@@ -20,13 +20,15 @@ class SHAMapDiffNode
 		mNodeID(id), mOurHash(ourHash), mOtherHash(otherHash) { ; }
 };
 
-bool SHAMap::walkBranch(SHAMapTreeNode* node, SHAMapItem::pointer otherMapItem, bool isFirstMap,
+bool SHAMap::walkBranch(SHAMapTreeNode* node, SHAMapItem::ref otherMapItem, bool isFirstMap,
 	SHAMapDiff& differences, int& maxCount)
 {
 	// Walk a branch of a SHAMap that's matched by an empty branch or single item in the other map
 	std::stack<SHAMapTreeNode*> nodeStack;
 	nodeStack.push(node);
-	
+
+	bool emptyBranch = !otherMapItem;
+
 	while (!nodeStack.empty())
 	{
 		SHAMapTreeNode* node = nodeStack.top();
@@ -41,7 +43,7 @@ bool SHAMap::walkBranch(SHAMapTreeNode* node, SHAMapItem::pointer otherMapItem,
 		{ // This is a leaf node, process its item
 			SHAMapItem::pointer item = node->getItem();
 
-			if (otherMapItem && (otherMapItem->getTag() < item->getTag()))
+			if (!emptyBranch && (otherMapItem->getTag() < item->getTag()))
 			{ // this item comes after the item from the other map, so add the other item
 				if (isFirstMap) // this is first map, so other item is from second
 					differences.insert(std::make_pair(otherMapItem->getTag(),
@@ -49,11 +51,12 @@ bool SHAMap::walkBranch(SHAMapTreeNode* node, SHAMapItem::pointer otherMapItem,
 				else
 					differences.insert(std::make_pair(otherMapItem->getTag(),
 						std::make_pair(otherMapItem, SHAMapItem::pointer())));
-				if (--maxCount <= 0) return false;
-				otherMapItem = SHAMapItem::pointer();
+				if (--maxCount <= 0)
+					return false;
+				emptyBranch = true;
 			}
 
-			if ((!otherMapItem) || (item->getTag() < otherMapItem->getTag()))
+			if (emptyBranch || (item->getTag() < otherMapItem->getTag()))
 			{ // unmatched
 				if (isFirstMap)
 					differences.insert(std::make_pair(item->getTag(), std::make_pair(item, SHAMapItem::pointer())));
@@ -77,7 +80,7 @@ bool SHAMap::walkBranch(SHAMapTreeNode* node, SHAMapItem::pointer otherMapItem,
 		}
 	}
 	
-	if (otherMapItem)
+	if (!emptyBranch)
 	{ // otherMapItem was unmatched, must add
 			if (isFirstMap) // this is first map, so other item is from second
 				differences.insert(std::make_pair(otherMapItem->getTag(),