sincerely, from when I start with kettlebells, my arm have been growing by themselves thanks to the amount of undirect work they do.
By the way, in order to have a balanced ratio of strength in the arms, i have introduced in my routine the standing french presses that Pavel shows keeping the kb by the horns, that works wonders for those missing the last inch of a heavy military press, and a very funny but hard exercise that i read from a hard-style article from Antony diLuglio: the kb ball curls, that simply consists to curl the kb gripping the ball inspite of the hande. try it!
EX ALTO FULGOR