Nearly. Every. One.
This isn't some fringe gun-nut/collector population, this is just about everyone who buys a rifle. And frankly, part of me feels like that is what really bothers a large proportion of gun control advocates: they know as well as I do that the shape of a rifle doesn't affect its ability to be used in a mass shooting, they just really hate that people like rifles of that shape, and want to get some sort of culture war victory here.