diff --git a/src/cpp/ripple/Ledger.cpp b/src/cpp/ripple/Ledger.cpp
index 8bb7709e2..33344bcfd 100644
--- a/src/cpp/ripple/Ledger.cpp
+++ b/src/cpp/ripple/Ledger.cpp
@@ -256,6 +256,7 @@ bool Ledger::addTransaction(const uint256& txID, const Serializer& txn)
 		cLog(lsWARNING) << "Attempt to add transaction to ledger that already had it";
 		return false;
 	}
+	mValidHash = false;
 	return true;
 }
 
@@ -270,6 +271,7 @@ bool Ledger::addTransaction(const uint256& txID, const Serializer& txn, const Se
 		cLog(lsFATAL) << "Attempt to add transaction+MD to ledger that already had it";
 		return false;
 	}
+	mValidHash = false;
 	return true;
 }
 
diff --git a/src/cpp/ripple/LedgerMaster.cpp b/src/cpp/ripple/LedgerMaster.cpp
index b671240b4..df3f3b15c 100644
--- a/src/cpp/ripple/LedgerMaster.cpp
+++ b/src/cpp/ripple/LedgerMaster.cpp
@@ -18,6 +18,14 @@ uint32 LedgerMaster::getCurrentLedgerIndex()
 	return mCurrentLedger->getLedgerSeq();
 }
 
+Ledger::ref LedgerMaster::getCurrentSnapshot()
+{
+	if (!mCurrentSnapshot || (mCurrentSnapshot->getHash() != mCurrentLedger->getHash()))
+		mCurrentSnapshot = boost::make_shared<Ledger>(boost::ref(*mCurrentLedger), false);
+	assert(mCurrentSnapshot->isImmutable());
+	return mCurrentSnapshot;
+}
+
 void LedgerMaster::addHeldTransaction(Transaction::ref transaction)
 { // returns true if transaction was added
 	boost::recursive_mutex::scoped_lock ml(mLock);
diff --git a/src/cpp/ripple/LedgerMaster.h b/src/cpp/ripple/LedgerMaster.h
index 2d872bbdc..dddffaa42 100644
--- a/src/cpp/ripple/LedgerMaster.h
+++ b/src/cpp/ripple/LedgerMaster.h
@@ -26,6 +26,7 @@ protected:
 	TransactionEngine mEngine;
 
 	Ledger::pointer mCurrentLedger;		// The ledger we are currently processiong
+	Ledger::pointer mCurrentSnapshot;	// Snapshot of the current ledger
 	Ledger::pointer mFinalizedLedger;	// The ledger that most recently closed
 	Ledger::pointer mValidLedger;		// The highest-sequence ledger we have fully accepted
 	Ledger::pointer mPubLedger;			// The last ledger we have published
@@ -74,6 +75,9 @@ public:
 	// The current ledger is the ledger we believe new transactions should go in
 	Ledger::ref getCurrentLedger()		{ return mCurrentLedger; }
 
+	// An immutable snapshot of the current ledger
+	Ledger::ref getCurrentSnapshot();
+
 	// The finalized ledger is the last closed/accepted ledger
 	Ledger::ref getClosedLedger()		{ return mFinalizedLedger; }
 
diff --git a/src/cpp/ripple/NetworkOPs.h b/src/cpp/ripple/NetworkOPs.h
index ffaac4aef..45499c08e 100644
--- a/src/cpp/ripple/NetworkOPs.h
+++ b/src/cpp/ripple/NetworkOPs.h
@@ -183,6 +183,7 @@ public:
 	Ledger::ref		getClosedLedger()						{ return mLedgerMaster->getClosedLedger(); }
 	Ledger::ref		getValidatedLedger()					{ return mLedgerMaster->getValidatedLedger(); }
 	Ledger::ref		getCurrentLedger()						{ return mLedgerMaster->getCurrentLedger(); }
+	Ledger::ref		getCurrentSnapshot()					{ return mLedgerMaster->getCurrentSnapshot(); }
 	Ledger::pointer	getLedgerByHash(const uint256& hash)	{ return mLedgerMaster->getLedgerByHash(hash); }
 	Ledger::pointer	getLedgerBySeq(const uint32 seq);
 	void			missingNodeInLedger(const uint32 seq);
diff --git a/src/cpp/ripple/RPCHandler.cpp b/src/cpp/ripple/RPCHandler.cpp
index 93482b0d6..0ec133cf7 100644
--- a/src/cpp/ripple/RPCHandler.cpp
+++ b/src/cpp/ripple/RPCHandler.cpp
@@ -177,8 +177,7 @@ Json::Value RPCHandler::transactionSign(Json::Value jvRequest, bool bSubmit)
 				return rpcError(rpcINVALID_PARAMS);
 			}
 
-			Ledger::pointer lSnapshot = boost::make_shared<Ledger>(
-				boost::ref(*mNetOps->getCurrentLedger()), false);
+			Ledger::pointer lSnapshot = mNetOps->getCurrentSnapshot();
 			{
 				ScopedUnlock su(theApp->getMasterLock());
 				bool bValid;
@@ -1031,6 +1030,9 @@ Json::Value RPCHandler::doAccountLines(Json::Value jvRequest, int& cost, ScopedL
 	if (!lpLedger)
 		return jvResult;
 
+	if (lpLedger->isImmutable())
+		MasterLockHolder.unlock();
+
 	if (!jvRequest.isMember("account"))
 		return rpcError(rpcINVALID_PARAMS);
 
@@ -1065,9 +1067,6 @@ Json::Value RPCHandler::doAccountLines(Json::Value jvRequest, int& cost, ScopedL
 
 	AccountState::pointer	as		= mNetOps->getAccountState(lpLedger, raAccount);
 
-	if (lpLedger->isImmutable())
-		MasterLockHolder.unlock();
-
 	if (as)
 	{
 		jvResult["account"]	= raAccount.humanAccountID();
@@ -1124,6 +1123,9 @@ Json::Value RPCHandler::doAccountOffers(Json::Value jvRequest, int& cost, Scoped
 	if (!lpLedger)
 		return jvResult;
 
+	if (lpLedger->isImmutable())
+		MasterLockHolder.unlock();
+
 	if (!jvRequest.isMember("account"))
 		return rpcError(rpcINVALID_PARAMS);
 
@@ -1852,6 +1854,9 @@ Json::Value RPCHandler::doLedger(Json::Value jvRequest, int& cost, ScopedLock& M
 	if (!lpLedger)
 		return jvResult;
 
+	if (lpLedger->isImmutable())
+		MasterLockHolder.unlock();
+
 	bool	bFull			= jvRequest.isMember("full") && jvRequest["full"].asBool();
 	bool	bTransactions	= jvRequest.isMember("transactions") && jvRequest["transactions"].asBool();
 	bool	bAccounts		= jvRequest.isMember("accounts") && jvRequest["accounts"].asBool();
@@ -1861,15 +1866,6 @@ Json::Value RPCHandler::doLedger(Json::Value jvRequest, int& cost, ScopedLock& M
 								| (bTransactions ? LEDGER_JSON_DUMP_TXRP : 0)
 								| (bAccounts ? LEDGER_JSON_DUMP_STATE : 0);
 
-	if ((bFull || bAccounts) && !lpLedger->isImmutable())
-	{ // For full or accounts, it's cheaper to snapshot
-		lpLedger = boost::make_shared<Ledger>(*lpLedger, false);
-		assert(lpLedger->isImmutable());
-	}
-
-	if (lpLedger->isImmutable())
-		MasterLockHolder.unlock();
-
 	Json::Value ret(Json::objectValue);
 	lpLedger->addJson(ret, iOptions);
 
@@ -2612,7 +2608,7 @@ Json::Value RPCHandler::lookupLedger(Json::Value jvRequest, Ledger::pointer& lpL
 
 	switch (iLedgerIndex) {
 	case LEDGER_CURRENT:
-		lpLedger		= mNetOps->getCurrentLedger();
+		lpLedger		= mNetOps->getCurrentSnapshot();
 		iLedgerIndex	= lpLedger->getLedgerSeq();
 		break;