This re-skin for the 'Groza' gives it a darker look, better handle, and better magazine. In my opinion, it looks sexier and more realistic than the default one. Check it out.
Extract the files in your S.T.A.L.K.E.R. directory which for retail buyers should be located in C:/Program files/THQ/S.T.A.L.K.E.R. -Shadow of Chernobyl/Gamedata/ and for Steam users it should be located in C:Program files/Steam/SteamApps/Common/Stalker shadow of Chernobyl/gamedata