Some do it here in Texas for pigs. It's a combo of ammo design and modifications to the rifles, its not a case of screw a suppressor to the barrel and go. The ammo has to be sub sonic. I believe you have to have a permit to own such a rifle.
As for practicality a bow would be cheaper
Navin R. Johnson: "He hates these cans!!!! Stay away from the cans!!!!"