[quote=The Fifth Horseman;
Sometimes it might be worth considering to take some HE ammo (altough not into terror missions, obviously).[/quote]
i ues it at terror too and sometimes shoot randomly at hidden movement. helps a lot. As well as phosphorus ammos (to light up the area and maybe burn an alien or two). In fact in begining of game i use HE exclusively. that is because their aim is low and they get kills fast like that (one shot two or three kills).
Also aliens tend to likie certain areas so what i do is shoot a few explosive rouds in those areas. it usually causes alien massacre.
the next good thing is that sometimes you see an alie but they are not in the line of fire. well with HE ammo there is nothing more simple. you just shoot next to them and send them into alien hell.
Another plus is that you can afford to have a little lower aim %, and as a result you can have a primed grenade in the other hand.
sure there is "collateral damage" on terror mission, but afterall this is about survival of all man kind not some shop owners or tourists...
i do it even better in TFTD, because i know the maps and their "hiding" places better, so collateral damage there is much smaller. and i finish missions faster.