diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2160073cfb55..4caa0184d2ff 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -47,6 +47,10 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * [#248](https://github.com/crypto-org-chain/cosmos-sdk/pull/248) Init btree store lazily to save allocations when no content insert into it.
 * [#252](https://github.com/crypto-org-chain/cosmos-sdk/pull/252) Add `BlockGasWanted` to `Context` to support feemarket module.
 
+### Improvements
+
+* [#]() `ctx.BlockHeader` don't do protobuf deep copy, shallow copy seems enough, reduce scope of mutex in `PriorityNonceMempool.Remove`.
+
 ## [Unreleased-Upstream]
 
 ### Bug Fixes
diff --git a/types/context.go b/types/context.go
index 50452e13b79e..2bf02578ca17 100644
--- a/types/context.go
+++ b/types/context.go
@@ -7,7 +7,6 @@ import (
 
 	abci "github.com/cometbft/cometbft/abci/types"
 	cmtproto "github.com/cometbft/cometbft/proto/tendermint/types"
-	"github.com/cosmos/gogoproto/proto"
 
 	"cosmossdk.io/core/comet"
 	"cosmossdk.io/core/header"
@@ -111,8 +110,7 @@ func (c Context) BlockGasWanted() uint64                        { return c.block
 
 // clone the header before returning
 func (c Context) BlockHeader() cmtproto.Header {
-	msg := proto.Clone(&c.header).(*cmtproto.Header)
-	return *msg
+	return c.header
 }
 
 // HeaderHash returns a copy of the header hash obtained during abci.RequestBeginBlock
diff --git a/types/mempool/priority_nonce.go b/types/mempool/priority_nonce.go
index f0df79e70882..03e909475696 100644
--- a/types/mempool/priority_nonce.go
+++ b/types/mempool/priority_nonce.go
@@ -429,8 +429,6 @@ func (mp *PriorityNonceMempool[C]) CountTx() int {
 // Remove removes a transaction from the mempool in O(log n) time, returning an
 // error if unsuccessful.
 func (mp *PriorityNonceMempool[C]) Remove(tx sdk.Tx) error {
-	mp.mtx.Lock()
-	defer mp.mtx.Unlock()
 	sigs, err := mp.cfg.SignerExtractor.GetSigners(tx)
 	if err != nil {
 		return err
@@ -443,6 +441,9 @@ func (mp *PriorityNonceMempool[C]) Remove(tx sdk.Tx) error {
 	sender := sig.Signer.String()
 	nonce := sig.Sequence
 
+	mp.mtx.Lock()
+	defer mp.mtx.Unlock()
+
 	scoreKey := txMeta[C]{nonce: nonce, sender: sender}
 	score, ok := mp.scores[scoreKey]
 	if !ok {