How to unlock the Sinful Butterfly in MGS V: The Phantom Pain

Sinful Butterfly is special weapon Brennan LRS-46 which is used by Buddy Quiet in Metal Gear Solid V: The Phantom Pain. First, everybody hated Quiet as she didn't do anything at all after posting up in the mission drop zone and finding her perch. Her Weapons are customized and she'll name them herself like the Sinful Butterfly for Brennan LRS-46. Here is how you unlock the Sinful Butterfly in MGS V: The Phantom Pain.

How to Unlock the Sinful Butterfly
To unlock the Sinful Butterfly, you need to find the Brennan LRS-46 Blueprint. You'll get a chance to grab it during your Main Mission 28 - 'Code Talker'. It will be inside the mansion to the east of ​Lufwa Valley. This Blueprint is kept on the cupboard in the library, on the western part of the house. 

Note: This mission has you’ll be ambushed by Skulls so make sure you're ready with some heavy weaponry.

Brennan LRS-46 is a sniper rifle which is a powerful but slow weapon. Use this Blueprint to upgrade Brennan LRS-46 to Grade 5 to increase the accuracy. Quiet will customize this weapon and name it Sinful Butterfly.