Millenia's AKS-74U

How to install:

At the moment of release GO doesn't support modding directly, so installation can be
a bit tricky and you'll need to edit pak01_dir.vpk every time Valve/HPE releases a
patch that updates that file. This'll hopefully change at some point after launch.

1) unarchive the materials & models folders into steamapps/common/Counter-Strike Global Offensive/csgo/
2) BACK UP PAK01_DIR.VPK IN CASE YOU SCREW SOMETHING UP!
3) open up pak01_dir.vpk in Notepad++ or some other proper editor
(Regular notepad will probably break your pak01_dir.vpk, so don't use that)
4) Use find & replace to find all instances of rif_ak47 and replace those with 
anything else, say, rif_ak48 for ease. What this does is basically it points the
VPK to a file that doesn't exist, and forces it to load loose files - ie. my model/textures.
5) Go in game and enjoy!

How to uninstall:

Restore backed-up pak01_dir.vpk. You can delete models/weapons/*_rif_ak47.*
and materials/models/weapons/Millenia/AKS-74U, if you so wish. Not necessary, tho.