diff --git a/msg_helpers.go b/msg_helpers.go
index 81fc2b1b..a5b342e3 100644
--- a/msg_helpers.go
+++ b/msg_helpers.go
@@ -223,8 +223,8 @@ func unpackUint48(msg []byte, off int) (i uint64, off1 int, err error) {
 		return 0, len(msg), &Error{err: "overflow unpacking uint64 as uint48"}
 	}
 	// Used in TSIG where the last 48 bits are occupied, so for now, assume a uint48 (6 bytes)
-	i = uint64(uint64(msg[off])<<40 | uint64(msg[off+1])<<32 | uint64(msg[off+2])<<24 | uint64(msg[off+3])<<16 |
-		uint64(msg[off+4])<<8 | uint64(msg[off+5]))
+	i = uint64(msg[off])<<40 | uint64(msg[off+1])<<32 | uint64(msg[off+2])<<24 | uint64(msg[off+3])<<16 |
+		uint64(msg[off+4])<<8 | uint64(msg[off+5])
 	off += 6
 	return i, off, nil
 }