The Raptr Weapon Tag can be acquired for free from Raptr Store for 250 Raptr Points (RP). Creating an account on their site awards 500 RP for free.
Originally, the Raptr Weapon Tag was given to raptr users who acquired the Hardcore rank, along with 2 Premade Weapons. These items were found inside the Raptr Legendary Package.
Prior to Parity update, when equipped this Weapon Tag would provide a +1 run speed bonus.