This is 6.5×55 Swedish Mauser 139gr. FMJ Ammo.
This ammo is manufactured by Prvi Partizan in Serbia.
The Prvi Partizan ammunition plant manufactures ammo for military use around the world, and is well known for their superior quality ammunition.
This ammo has a 139gr. FMJ bullet. It is brass cased, boxer primed and 100% non-corrosive.