0. Backup your files!
1. Open your IMGed, or ImgTool or some program like that.
2. Open in the application your vice citys gta3.img file (From models folder!)
3. Search for ruger.dff and replace it with the one incuded in the ZIP
4. Then search for ruger.txd and replace it with the one in ZIP
5. Close the application, then open your vice city and enjoy new AK!