MW 30 in Data

With the notable difference of it spreading its damage unevenly, while Torpedo is an even spread. So, assuming each monster gets KB'd, Torpedo wins, because Pierce would kill 1 monster faster, then the next, etc, slowly losing DPS while even-spread attacks would not.

In this scenario, we're talking about bosses.
In a training scenario, the back monster would die first, thus DPS to the front monsters won't change at all. Net DPS will go down because there's one less monster, but the same can be applied to the first monster for the Corsair, due to Bullseye, and even more so because the Corsair would then have to use another Bullseye.