to have this complete You need M4 brass inserts, see link bellow.
https://www.3djake.cz/3djake/zavitove-vlozky-50dilna-sada?sai=9420&gclid=EAIaIQobChMI4fT8h9Ga-wIVkgeLCh2ZTQiUEAQYASABEgI54fD_BwE
https://www.youtube.com/watch?v=Zg7qq8Ba-D0
The author hasn't provided the model origin yet.