You'll automatically acquire this weapon from a box during the Packing Up Chapter. Upon acquiring this weapon you'll want to add the Damage and Fire Rate upgrades to it, as a headshot with this gun can take down an enemy with a single bullet.
Join Ellie and Dina, as they have to overcome difficult puzzles and encounters whilst traveling through Seattle. During this adventure you'll be able to find Artefacts for interesting backstory, Trading Cards for Ellie to collect, and Weapons to make the more difficult encounters easier.
The guide for The Last of Us: Part II will include all there is to see and do including a walkthrough featuring how to take down all encounters, locate all Collectibles/Weapons, and how to solve all puzzles.