Whenever me or my friend play chaos dwarves, we always take at least two big units of blunderbusses. The reason is obvious - with their massive fire power they can prevent most units from even getting near them. In fact, usually even heavy cav couldnt get near them without being shot to pieces and ending up too weak to win the cc. Dwarves are decent fighters and with their LD 9 its very hard to break them.

For a point cost of 11 points per model one can create a unit that can hold off almost all enemies... a clear case of an overpowered unit IMO.

In the last few games we changed the rules slightly. Instead of always hitting on a 4+, the normal modifiers apply to blunderbuss fire. E.g. if they shoot after moving or if shooting against charging enemies they would get -1 to hit, thus hitting on a 5+. (And of course they also get a +1 modifier against large targets .)

Since we've been playing with this variation the blunderbusses are much more evened out. They are still a powerful unit, due to their S5 (with 3 ranks) and are definitely worth the points.
But they are not uberpowered anymore. With infantry its still hard to get near them, but at least heavy cav can charge them without being blasted to bits.

What do you think of the rule?

great idea! my saurus even have trouble with attacking them, not to mention my skinks, im just lucky they have a 12" "fire zone".

quite a good idea, i too am a fan of a shooting line of blunderbusess, for me blunderbusses are evened out though because to get (and keep) the strength bonus you need to buy a lot and you dont really get the benefit of massed fire that other races do.

Their small fire zone means they are easy to out manuveure and they are useless against single (large or otherwise) models or units that are few in number but high wounds/toughness.

I think they are quite a tactically demanding unit to both play against and use effectivly.

Would I go without them - never!