How about HK 416
For some reason the list is in absolutely no logical order. Not sure what sets the order in the loadout menu. Look for "HK 416 (D10RS) Enhanced Carabine".
Look at this screen shot. I think it should be ordered the same way in your menu.
If you do not see it, look in the Infiltration.log for errors. If you are not sure how to read the infiltration.log just do this.
1) Open INF.
2) Go to the loadout menu and select a loadout to edit and browse through the automatic rifle category
3) quit INF.
4) find the infiltration.log in ...\UnrealTournament\System\Infiltration.log
5) Post it in this thread