Originalism is an approach to constitutional interpretation which emphasizes legislative history and text analysis over subsequent practice and legal precedent; the religious analogy would be Protestantism. Given the nature of the Second Amendment and the state of the case law, the Heller case should have been a showcase for Scalia (ironically, an unabashed Catholic) and originalism. And so it was, but in a negative way. Scalia unscrupulously cherry-picked history, disregarded the actual intent of the framer of the Second Amendment (Madison), and somehow read the language of the amendment pertaining to the militia to give the public individual rights to carry weapons which have no military utility. It is a masterpiece of judicial b.s. In the long run, I believe it will be viewed as the right-wing equivalent of Roe v. Wade.
All that said, gun control legislation is notoriously difficult to enforce, and gun ownership would be protected by the Fifth and Fourteenth Amendments even if the Second Amendment didn’t exist, so the mere finding of an individual right to own a gun in Heller is not, to me, necessarily a catastrophe. Scalia conceded that the right to own and carry a gun is not absolute, and is subject to reasonable regulation based on common historical practice. The real question, then, is what level of scrutiny will be applied to gun regulations in the future. Heller leaves that question unanswered.
It appears that an answer will be coming soon, and it doesn’t look good. The likelihood is that the next big gun case will focus largely on the ridiculous task of determining whether an AR-15 is the modern equivalent of a musket, based on the level of ownership and its destructive power. That is an inquiry which has no basis in either the text or the real legislative history of the Second Amendment. Given the ideological leanings of the current Supreme Court, bet that they will decide that the right to own a semi-automatic rifle is sacrosanct.