you have some strange firearms regulations in the USA, anyone can own a gun but not a suppressor..
a suppressor is just a metal tube, some shins and springs.. most plumbers have everything needed to build a suppressor in their toolbox.
here in Iceland we have extremely strict regulation about owning firearms and how they are kept but a suppressor is not a firearm and anyone can own one, the only limitation is using them.. to put a suppressor on a gun is modification and for that we need a permit, but for building one and having it is not limited in any way, even kids can build and own suppressors but they can't own or use guns.
for rifles at the range a suppressor should be mandatory, shooting a .300WM with a suppressor is like shooting a .22LR, there is no need for hearing protection.