Ovinomancer
No flips for you!
I agree that a bow should not be treated as a 'held object,' but I think it should be treated as a melee weapon during a sunder attempt. Only those bonuses that apply to a melee strike should be used. Point blank and other range specific feats should not count, STR instead of DEX, and a potential non-proficiency penalty should apply. Weapon focus is hazy, but I would allow it because a fighter throwing a weapon not designed to be thrown would still get the bonus.
Of course, this relies on the thought that the archer is trying to block the attempt by moving his bow to ward off the brunt of the attack. If you want to imagine that he is firing an arrow to block it, I would say he gets his full ranged attack bonus. But I want to see him mark off the ammunition.
No. If I disobey my wife, I get sent to the couch. If I disobey my GM, I get sent back to my wife.
Good thing she doesn't read these posts, or I would be sent to someone else's couch.
Of course, this relies on the thought that the archer is trying to block the attempt by moving his bow to ward off the brunt of the attack. If you want to imagine that he is firing an arrow to block it, I would say he gets his full ranged attack bonus. But I want to see him mark off the ammunition.

Under orders... He thinks I'm his wife again
No. If I disobey my wife, I get sent to the couch. If I disobey my GM, I get sent back to my wife.

Good thing she doesn't read these posts, or I would be sent to someone else's couch.
