比如说这里提到的
Q:Is It possible to use many shot feat in combination with rapid shot? for
instance i'm using rapid shot to have one additional attack and then use
manyshot feat to add more damage with arrows
A:No.Taking a Manyshot is a standard action (not a single attack);
Rapid Shot requires a Full Attack action. You cannot take multiple
standard actions as part of a Full Attack, so you can't make more
than one Manyshot in a round (I suspect you've made this mistake
in your campaign, given the question).
Why would you ever use Manyshot, you may ask?
(1) If you need to move or take some other move-equivalent action
during the round (but I'm pretty sure you can't use Shot on the
Run with Manyshot, either, since it specifically mentions "the
attack action")
(2) True Strike
(3) Not limited to 4 attacks in a round (5 with Rapid Shot) -- if your
BAB if +26, you get to fire 7 arrows (at -14...)
(4) There's a feat that allows you to distribute the shots against
multiple targets