diff --git a/conn.go b/conn.go
index 6a552d8..34cf0b9 100644
--- a/conn.go
+++ b/conn.go
@@ -17,7 +17,6 @@ package nftables
 import (
 	"fmt"
 	"sync"
-	"sync/atomic"
 
 	"github.com/google/nftables/expr"
 	"github.com/mdlayher/netlink"
@@ -41,7 +40,7 @@ type Conn struct {
 	sync.Mutex
 	put      sync.Mutex
 	messages []netlink.Message
-	entities map[int32]Entity
+	entities map[int]Entity
 	it       int32
 	err      error
 }
@@ -52,7 +51,6 @@ func (cc *Conn) Flush() error {
 	defer func() {
 		cc.messages = nil
 		cc.entities = nil
-		cc.it = 0
 		cc.Unlock()
 	}()
 	if len(cc.messages) == 0 {
@@ -71,7 +69,7 @@ func (cc *Conn) Flush() error {
 
 	cc.endBatch(cc.messages)
 
-	_, err = conn.SendMessages(cc.messages[:cc.it+1])
+	_, err = conn.SendMessages(cc.messages)
 
 	if err != nil {
 		return fmt.Errorf("SendMessages: %w", err)
@@ -104,36 +102,29 @@ func (cc *Conn) Flush() error {
 }
 
 // PutMessage store netlink message to sent after
-func (cc *Conn) PutMessage(msg netlink.Message) int32 {
+func (cc *Conn) PutMessage(msg netlink.Message) int {
 	cc.put.Lock()
 	defer cc.put.Unlock()
 
 	if cc.messages == nil {
-		cc.messages = make([]netlink.Message, 16)
-		cc.messages[0] = netlink.Message{
+		cc.messages = append(cc.messages, netlink.Message{
 			Header: netlink.Header{
 				Type:  netlink.HeaderType(unix.NFNL_MSG_BATCH_BEGIN),
 				Flags: netlink.Request,
 			},
 			Data: extraHeader(0, unix.NFNL_SUBSYS_NFTABLES),
-		}
+		})
 	}
 
-	i := atomic.AddInt32(&cc.it, 1)
+	cc.messages = append(cc.messages, msg)
 
-	if len(cc.messages) <= int(i) {
-		cc.messages = resize(cc.messages)
-	}
-
-	cc.messages[i] = msg
-
-	return i
+	return len(cc.messages) - 1
 }
 
 // PutEntity store entity to relate to netlink response
-func (cc *Conn) PutEntity(i int32, e Entity) {
+func (cc *Conn) PutEntity(i int, e Entity) {
 	if cc.entities == nil {
-		cc.entities = make(map[int32]Entity)
+		cc.entities = make(map[int]Entity)
 	}
 	cc.entities[i] = e
 }
@@ -214,23 +205,14 @@ func (cc *Conn) marshalExpr(e expr.Any) []byte {
 
 func (cc *Conn) endBatch(messages []netlink.Message) {
 
-	i := atomic.AddInt32(&cc.it, 1)
+	cc.put.Lock()
+	defer cc.put.Unlock()
 
-	if len(cc.messages) <= int(i) {
-		cc.messages = resize(cc.messages)
-	}
-
-	cc.messages[i] = netlink.Message{
+	cc.messages = append(cc.messages, netlink.Message{
 		Header: netlink.Header{
 			Type:  netlink.HeaderType(unix.NFNL_MSG_BATCH_END),
 			Flags: netlink.Request,
 		},
 		Data: extraHeader(0, unix.NFNL_SUBSYS_NFTABLES),
-	}
-}
-
-func resize(messages []netlink.Message) []netlink.Message {
-	new := make([]netlink.Message, cap(messages)*2)
-	copy(new, messages)
-	return new
+	})
 }