Lynata said:
Umm... given that Rogue Trader and Ascension were written before Deathwatch, the Unarmed Warrior and Unarmed Master talents appeared in those books first. It's far from it being a matter of a Deathwatch-specific rule creeping into DH or RT.
Damage is abstract, remember; the combination of brute force, precision, location struck (is it a flesh wound? Did it graze the bone? Did it strike a major organ?), timing and a variety of other factors. A character with Mighty Shot deals more damage with the same lasgun than someone without that Talent because he knows how to better employ the weapon's power, and the power that weapon discharges is the same with every pull of the trigger - the variable nature of damage is a matter of circumstance and blind luck as much as anything else. Same with basic weapons with the Accurate quality - a Long-Las discharge isn't more powerful than a plasma gun, but it is far more precisely applied than a normal lasgun discharge, granting it the effect of extra damage in game terms.
A character dealing 1d10+4 damage with his fists, feet, shins, elbows, etc, isn't strictly applying greater force than a Lasgun discharge... what he's doing is ensuring that the force he is applying is going where it is most effective.

Deal with it.