Yeah.... @Gretorion we're going to need you to post some actual words to go with these pictures, and read up on The Rules if you don't mind... They'll explain all about posting in the right place, how to ask a question properly, searching for your answer before you post, how to structure an introductory post, etc...
Welcome to the asylum. If you have any questions about policy or procedures not covered in the rules feel free to message a staff member.
Barrel threads on an unknown HP carbine. Well….good news, you have 50% chance of getting it right. They do make bullpup stocks in both sizes, right?
It’s either .578x28, or it’s 1/2x28. Make sure you don’t get a 5.56 device.
No idea why you’re asking, the gun looks good. Suppressor maybe?