To get the Harran Military Rifle for PC, update your game first, please. Then, go to the product's website, sign up for a free Gemly account and add the product to your account:


Steam:

https://gemly.com/shop/Dying-Light---Harran-Military-Rifle-4100000/4100000101


GOG:

https://gemly.com/shop/Dying-Light---Harran-Military-Rifle-4100000/4100000102


Once you add the DLC to your game, the rifle comes in the form of a blueprint, which can be found in the game in the Blueprints section (not the Inventory):