This is normal scheduling for any SCOTUS case.
The judges probably had made their individual decisions when they took the case in the first place (there really isn't that much subsequently new to change their minds on a well-established, if controversial, subject). They then had to wait for the main parties, and their friends, to submit nearly a half-million words of argument on all sides and many tangents to the subject. Then they had to perform the theatrical activity of "oral arguments" where much is discussed but little is said. Then they have to figure out where each judge stands on the issue, aggregate into varying/conflicting points of view, figure out what the majority actually agrees on, and figure out how minority views will be expressed. Then they have to discuss what the consequences of the verdict are and how those will be addressed. Then they have to write a long and incredibly carefully worded document stating the verdict and reasons by which that was reached, and define limits & openings to the scope of that ruling. Then they have to get it printed, archived, and distributed.
It's not a simple process.
Especially when a majority of the judges know what the verdict should be, but are terrified of "third rail" consequences such as that a direct consequence will be the full legalization of machineguns.
Every place I've posted that news, I've been typically getting a response of 'Who is Paul Clement?'. Uh, he's the former Solicitor General who argued on behalf of the US government in DC v. Heller, remember him now?
He was one of Scalia's legal aides working on internship as a young law school graduate and later as Solicitor General argued for the government in Silviera v. Lockyer in the 9th Circuit Court of Appeals. It was a hysterical point against falling down the slippery slope towards legalizing machine guns if the petitioner Silviera should prevail.
Of the few places this news was even mentioned, I had read that there was a rumor that Clement resigned ahead of the finding in DC v. Heller because he'd gotten wind of the internal debate at SCOTUS gleaned from their legal aides as well as what legal references they were researching on behalf of the individual justices.
Sounds like rumor, of course. I can certainly tell you that I don't miss him a bit.
I see nothing wrong with the price of an M4A1, with M203 attached, and ACOG scope all for under the price of $5000.
Heck, depending on who you get an AR-15 from, it could be the price of an ACOG scope, or either way from its price. With the scope, it could easily become a $2000 rifle.