Not particularly the sort of information the NRA would be prone to publicizing in their advertising campaigns, and with most shooters dead, not the sort of thing said shooters be bragging about either.
I read one account stating that Nikolas Cruz was a member, that he had said that's was how he managed to get the NRA to sponsor his rifle team in school, but I haven't been able to verify that.
Regardless, it is well known that the NRA has loads of lobbyists and they have certainly lobbied quite a few Republicans who have refused to vote yes on any gun control measures. There was one bill I recall during Obama or Bush that was removed before it could be voted on by Congress because the NRA said they didn't like it. Not that my imprecise recollection is anything worth citing, but, whatever.
It's not like the NRA is commanding members to go on mass shootings sprees, but neither does Marilyn Manson to his fans, and people had no trouble trying to blame Columbine on him. Doubtful whether or not those shooters were paid members of the Marilyn Manson fan club and that that would have had played a role in what they did. For all we know Marilyn Manson had kept them calm at least for a few years.
The US Bacon Association isn't going around injecting mass quantities of cholesterol in people's veins, but that doesn't mean that the product they promote might not still have negative effects on people's health if consumed excessively on a fairly regular basis.
btw, for those wondering, I made up the US Bacon Association, but you get my point.
