Like Go-Around, I have found the smaller operators much more willing to repsond, sometimes personally, to my CV and letter.
I sent a batch of 31 CVs out in early December and to date have had 14 responses (mostly written and a handful by email).
The vast majority of the non-responses have been from what I class as the "larger" airlines (big companies, all jet fleets). The vast majority of the turboprop airlines and regional airlines have responded in one form or another.
But certainly keep firing them you never know when you might strike gold.