Your local shops just cater to "Joe Six Pack". .20 caliber isn't really mainstream, though sometimes it seems so in our internet forums. Specialty online sources are where you will have to look.
Danny
I guess I am one of the fortunate one's as my local gun shop caters to the 17 & 20 caliber guys. Lost of 204 R and 17 fb & reminton shooters in this area, even along with the push for AR and long range and bigger calibers.