I have to agree that we probably are no longer a nation of riflemen. I don't know what the tipping point would be, but I think today more of the population lives in cities and urban areas than lives in rural or even suburban areas, and a large percentage of urban dwellers not only don't shoot or own firearms, they are actively anti-gun.
I'm a senior citizen. When I grew up in the 1950s, we lived in a rural community in an extended family -- my maternal grandparents lived 3/10 of a mile down the road, and two sets of aunts, uncles, and cousins lived another 2/10 beyond the grandparents. My grandfather kept guns in his house. Both uncles kept guns in their houses. My father didn't, but he was a WW2 veteran, he knew how to use a gun, and when he needed one to dispatch a pesky groundhog he just borrowed one from one of the uncles.
My grandfather taught me to shoot when I was 8 or 9 years old. Around the age of ten my brother and I and all the cousins attended a day camp during the summer months. The camp activities included both riflery and archery, for both girls and boys. Many of the other kids attending that camp came from my home town.
I still live in the same town, but it's no longer rural. There is only one remaining farm, and as far as I can see it operates as a hobby farm, not as a viable, income-producing farm. We are now a suburban bedroom community. Somewhere along the way, the town enacted an ordinance that prohibited discharging firearms within town limits, and also prohibited carrying or possessing loaded firearms in town. There was no exception for carrying with a state-issued permit, and the police department said they considered the ordinance to be unenforceable. But ... it was on the books, and a future chief of police could have decided to enforce it. With the assistance of my state's grass roots pro-gun group, a good attorney, and some financial backing from the NRA I was able (after a two-year battle) to get the ordinance revised so that at least we're not breaking the law when driving through town with a loaded gun and a permit.
The point of that is that such laws don't grow out of communities made up of riflemen. Laws such as that are enacted by people who hate guns, and that became clear during a meeting with the town's governing body. I was there, my attorney was there, and several women from the grass roots group were there to emphasize the point that the [old] ordinance made my town dangerous for women. The lawyer went through all the reasons why the ordinance was unconstitutional and why it wouldn't stand up to a court challenge.
The mayor (a woman, and a professor of law at a nearby university) saw that some of the members of the panel seemed to be sympathetic to our position, so she derailed that in a hurry. "That's all very nice," she said, "but we don't like guns here."
And that was that. That ended the meeting, and there was no further progress until my lawyer made clear that we were going to file a lawsuit, and the town's attorney understood that the town would lose so he recommended revisions. But the revised ordinance still makes it unlawful to discharge a firearm anywhere in town except in lawful self defense, and it also prohibits discharging an air gun, air rifle, or bow and arrow anywhere in town.
How can we be a nation of riflemen when our kids can't even shoot a BB gun in the back yard without running the risk of being arrested? It's the end of the Daisy Red Ryder carbine.
To summarize: Are we still a nation or riflemen? Nope.