The Pittman/Roberts act (I think) imposed a federal tax on all sporting goods back in the 1930s. I'm not sure if all firearms are covered by this act, but I know things as mundane as fishing tackle boxes are, for sure!
I've noticed a lot more activity at my club and local ranges over the past year or so. Don't know if the lack of ammo available is the result of more gun owners using their gear or some other reason. I try to get out at least twice a month with 22, 380, 38, 9mm and/or 45acp.
__________________ The problem with socialism is that you eventually run out of other peoples' money.