Open IV is required*


Add-on method:
1) Go to GTAV/update/update.rpf/common/data/dlclist.xml

2) extract dlclist.xml

3) add this line underneath "<Item>dlcpacks:\patchday9ng\</Item>": 

<Item>dlcpacks:\metroidguys-addon-guns\</Item>

4) put folder metroidguys-addon-guns in: GTAV/update/x64/dlcpacks/
Note: be sure that when you put the folder there, the folder shows up, if you drag it there and only 
a file called "dlc.rpf" appears, then you have to create the folder "metroidguys-addon-guns" and put "dlc.rpf" there.

Replace method:
1) Go to GTAV/update/x64/dlcpacks/patchday8ng/dlc.rpf/x64/models/cdimages/weapons.rpf/(put the files here)