Replace your default AK-47 gun and always see " weapon data " , and for the sounds you can go to following link ( just choose one of them ) :

http://www.gtainside.com/en/sanandreas/mods/105812-day-of-infamy-fg-42-sounds
http://www.gtainside.com/en/sanandreas/mods/97013-fg-42-sounds

Enjoy :)

CREDIT : Hong Kong Pigs' Studio, Killer699