Mad3: Some time ago something strange happened.
I had a char with a natural strengh bonus who used a mighty bow.
The damage bonus was not shown on character sheet.
Then I cast bulls strengh on him.
Now the correct damage was shown on character sheet

it was something like this:
strengh 14, no bonus by item or spell, mighty longbow+3 ---> 1d8 damage on character screen
same as above but with bulls strengh = 18 strengh ---> 1d8+3 damage shown on character screen.

note: mighty longbow+3 means it is any longbow and the mighty bonus goes up to +3.

MadOverlord: So I got a little ambitious, and I might have figured it out.

Right as rain, my ordinary longbow is shown as giving 1d8+3 damage. I assume the +3 damage is the 1 1/2x str bonus.

But if you look at this picture I took in game, you notice a contradiction.
http://i427.photobucket.com/albums/pp351/IGiveUpArgh/LongbowDam2_zps45b38ced.jpg

Notice how the Orc was hit for only 1 damage, when the minimum should be 4. So I'm thinking it shows as bonus damage, but doesn't count as such.

Edit: My original explanation was clumsy, so I fixed it.

Coelocanth: What are they using for ammo?

*edit* Oh, and something tells me there was a problem with the character sheet when it comes to displaying damage from ranged weapons, in that it shows incorrect values (it treats any weapon as a melee weapon with regard to damage values. The bow would be looked at as a two-handed weapon, therefore the additional damage. This is not actually applied in-game. It's just a character sheet display glitch).

Did you check the damage values in-game to make sure you're actually getting the extra damage? (Forgive me if this is posted up-thread. It's late and I haven't the ambition to check all the posts).

Mad3: Some time ago something strange happened.
I had a char with a natural strengh bonus who used a mighty bow.
The damage bonus was not shown on character sheet.
Then I cast bulls strengh on him.
Now the correct damage was shown on character sheet

it was something like this:
strengh 14, no bonus by item or spell, mighty longbow+3 ---> 1d8 damage on character screen
same as above but with bulls strengh = 18 strengh ---> 1d8+3 damage shown on character screen.

note: mighty longbow+3 means it is any longbow and the mighty bonus goes up to +3.

I do not know if bows really do the wrong damage or if it is only the character sheet that is buggy.
I could not find out because the difference was only 1 point of damage and there might be other factors (enemies have damage resistance or weakness, some buffs are not shown, . . . who knows what)

Some experience from when I tried to play an archer:
-The damage is not shown correctly (see above). For example, the arcane archer bonus is not shown at all.
- Usually you fight several enemies at once. Avoiding melee combat completely is almost impossible, especially when your archer is a warrior and you don´t want to use a mage as tank
- At high levels archers burn their ammo with an insanely high rate. (At level 30 6 base attacs + rapid shot + haste =80arrows per minute)

I think in NWN archers are much less useful than in the baldurs gate series.

Coelocanth: If the game implements the Mighty properly correctly (and I can't recall if it does), then this would make sense. If your STR modifier is not as high as the Mighty property, you won't get the bonus damage. Since your STR modifier on that character was only +2 and the bow is Mighty +3, you won't get bonus damage (in fact, it should be a penalty). Once you cast Bull's STR, your modifier will be at least +3, and thus the extra damage will apply.

Again, I can't recall if the game correctly applies this rule.

tossacromwell: Mighty is supposed to give a strength bonus up to whatever number is next to the addition symbol. For example, Mighty +3 gives up to +3 but no more, so you could get +1, +2 or +3