There really weren't stores that sold only guns, they were just another item for sale. You could buy them at "The Western Auto" hardware, Sears and Roebucks, Kresge's, and a lot of Mom and Pop grocery stores. When we used to go back to Maine in the summer, the quickest way to get the kids out of your hair was to give each one a box of 50 22's and an old single shot and point them at the woods. 50 cents for a box of 50 22's in those days.
Prior to 1968 we bought a case of British Enfields (303 British). They came out of Burma. 12 rifles to a case and it worked out to less than $15 a rifle including the shipping. No government entity involved. No government entity had any knowledge of what you owned, nor did they have the right to even ask.
You used to be able to buy 6.5 Jap Arisakas from the back pages of magazines, much like they sell Viagra nowadays. When I was in Jr. High (not middle school) one of our more industrious German students had ordered a pen with a little bolt action .22 on the back of it. He shot himself in the hand with it in Geography one day. No lock down, no evacuation of the school or the county we just sat there and the nurse took him out. He was back in school a couple of days later. I think he did get detention though. Ah, the good old days.
This!!!
We use to carry our .22 rifles to school, stack them in the corner of the room, retrieve them at the end of the day and go plinking in the sand pit behind and ON school property. I boarded a DC-3 open carrying a S&W .38 Special and flew from Shreveport to San Antonio. No one said a word. No one batted an eye. Stopped at a bank to deposit some money open carrying. No one said a thing. In high school and college small arms and high powered markmanship were REQUIRED to graduate (so was fencing and archery).