MP5 magazine style chamber flag. Much easier to manage flagging and un-flagging when the mag catch holds the flag for you.
I used @DannyMeatball 's MP5 mag as a base to create this.
I printed in orange PETG but PLA or PLA+ would probably be good too. 2 walls, 15% infill, auto supports.
The author marked this model as their own original creation.