Prior to the NRA’s big push in the late seventies, gun control as a concept was uncontroversial as the first gun control laws dated back to the earliest days of the country. Reagan expanding coverage due to the Black Panthers was in line with earlier precedent (after Kennedy was assassinated, during WWII, during the Mob / prohibition era, etc.).

A bit more nuanced than that; the NRA didn’t become the hardline defender of minimal gun regs until its 1977 leadership shift. Reagan’s 1967 Mulford Act as Governor targeted the Black Panthers, and then he signed 1986 FOPA as president, which relaxed some rules but banned new machine guns. It was a broad compromise package from the start.

My focus was really the hardline individual right stance: I know people who left the NRA over that because they were sportsmen or retired military who thought it was quite reasonable to have civilian restrictions, especially mental / proficiency restrictions.