Ranged Sorcerer Options

It seems that people that play ranged sorcerer go either

dual pistols
OR
rifle + searing strike
(why no focus + pistol?)

and use either
fire strike
OR
black water

Im pretty new to the game and building a sorcerer…i started building it around calidors and it is working fine with decent gear but im too squishy so i decided to try the ranged root…can someone maybe give me some input of what is the benefit drawdown of each variant?