For those of you who might be wondering about the worth of the Assault skill Rapid Fire, here's the skinny on how the math breaks down.
Rapid Fire has a 15% penalty to Aim, so, for a given 75% normal shot, Rapid Fire will fire two 60% shots.
Assuming that your shot will deal 1 damage, for simplicity's sake, if you fire your gun 100 turns, on average you'd deal 75 damage with a normal shot and 120 damage with Rapid Fire.
This is because with Rapid Fire you have a 36% chance of hitting twice (0.6 * 0.6), a 48% chance of one shot hitting and one shot missing (0.6 * 0.4 + 0.4 * 0.6), and a 16% of both missing (0.4 * 0.4). The damage output there over 100 turns is 2 * 36 + 1 * 48 = 120.
So, on average, you want to be Rapid Fire-ing for most of your shots to increase your damage.
Just don't forget to reload twice as often.
EDIT: As a corollary, in this example, since your chance to miss both shots is 16%, then you want to be Rapid Firing in higher leverage situations too since your chance to hit at least once is 100 - 16 = 84%