VSR-10 Junk - Malfunction?

This is a VSR-10 that I purchased used a long time ago.
When I used it recently, the muzzle velocity/trajectory was terrible (velocity below 50 m/s), and it seems the internal mechanism has been completely replaced with something else. Finally, the bolt stopped returning (lol).

This is completely a junk item, so please understand before purchasing. I think it's best for parts.
I am open to price negotiations, but shipping may be cash on delivery. Please understand.
The rail will be included. A bipod can be included for an additional 1000 yen.