Well, if he really wants to be an originalist and follow the US Constitution AS WRITTEN, then he can't rule on the constitutionality of legislation: as that is not an enumerated role for the Supreme Court.
Instead, that comes from the case of Marbury v Madison, 5 U.S. (1 Cranch) 137 (1803). Marbury also says that no clause in the Constitution is without meaning, which means that Heller and McDonald are BS since they ignore a clause in the Second Amendment. I would add for good measure that the previous SCOTUS Second Amendment cases (Presser v. Illinois, 116 U. S. 252, and US v. Miller, 307 U.S. 174) Made it clear that the Second Amendment applied to the Militia, or current National Guard.
Miller contradicts the findings of the Heller and McDonald decisions saying:
"With obvious purpose to assure the continuation and render possible the effectiveness of such forces, the declaration and guarantee of the Second Amendment were made. It must be interpreted and applied with that end in view."
Justice William O Douglas, who was on the court when Miller was decided, gave a summary of that case in his dissent to Adams v. Williams, 407 U.S 143, 150 -51 (1972):
The leading case is United States v. Miller, 307 U. S. 174, upholding a federal law making criminal the shipment in interstate commerce of a sawed-off shotgun. The law was upheld, there being no evidence that a sawed-off shotgun had "some reasonable relationship to the preservation or efficiency of a well regulated militia." Id. at 307 U. S. 178. The Second Amendment, it was held, "must be interpreted and applied" with the view of maintaining a "militia."
According how the originalists claim their method of interpreting the constitution, a change from the Second Amendment applying to the Militia to allow for personal possession of firearms in the home would require and amendment: not occur through judicial fiat.
I would also add that the Constitution makes clear that it deals with matters of the common defence in the preamble and is silent on self-defence. Any first year law student knows that when a legal document is silent on an issue that that issue is not covered. There are a few other accepted rules of statutory interpretation which pretty much rule out that self-defence is addressed in the US Constitution and that the Second Amendment should be extended to allow for deadly weapons to be used for that purpose.
This adds in that the concept of self-defence in traditional common law is a mitigation, not an excuse. The black letter common law for this is:
Self-defence is a legal doctrine which says that a person may use reasonable force in the defence of themself or another.
Reasonable force is not in the mind of the person claiming self-defence, but in the finder of fact's (jury or judge) opinion. But the rule is pretty much that deadly force is NOT allowed unless there are extreme circumstances.
This might be the time to push this issue. No matter what, I would like an answer on the matter of how an "originalist" can somehow rule on constitutionality since that is not found in the text of the Constitution.
Even more importantly, an Originalist should not go against precedent and the Constitution as written. I am not sure how one would handle overturning a law for unconstitutionality since that is not a role given to the Supreme Court in the Constitution. Instead, it is found in custom.
On the other hand, now might be the time to find out how exactly a justice would handle this dilemma if they claim that they obey the constitution as written and any real change requires an amendment.