Will the Supreme Court rule that the Second Amendment protects AR-15 rifles, striking down the Illinois and Connecticut bans, by July 3, 2027?

The Court chose this fight. Justice Kavanaugh wrote in June 2025 that the Court should and presumably would take up the AR-15 issue in the next term or two, and Justices Thomas, Alito and Gorsuch wanted to hear a Maryland ban right away. Four justices voting to grant a case they have publicly criticized is a strong sign they expect to win it, because a grant that ends in an affirmance would lock the bans in nationwide.

The swing justices are Chief Justice Roberts and Justice Barrett. Both joined Justice Alito's 6-3 majority in Wolford v. Lopez in June 2026, and Barrett wrote separately that courts may not smuggle regulatory limits into the plain text step of the Bruen test. That is the exact step where the Seventh Circuit upheld Cook County's ban, by treating AR-15s as military weapons outside the Second Amendment. Roberts prefers narrow rulings, which is the main path to a NO: a remand that tells lower courts they used the wrong test without saying AR-15s are protected.

The federal government, which usually defends gun laws, filed a brief on September 4, 2026 supporting the challengers. That removes the Solicitor General as a counterweight and gives cautious justices institutional cover to rule broadly.

The reference class is Second Amendment cases the Court has decided on the merits since District of Columbia v. Heller in 2008: Heller, McDonald (2010), Caetano (2016), Bruen (2022), Rahimi (2024), Hemani (2026) and Wolford (2026). The gun-rights side won six of the seven. The single loss, Rahimi, involved disarming people under domestic violence restraining orders, where the government had a strong history of disarming dangerous individuals.

The closest analogue is Heller itself, which struck down a ban on an entire class of arms, handguns, because they were the quintessential self-defense weapon in common use. Challengers argue AR-15s fit the same common use test. The analogy breaks because Heller said weapons most useful in military service, like M-16 rifles, may be banned, and the states argue AR-15s are close enough to M-16s to fall in that category. How the justices handle that line is the whole case.

Where history warns against overconfidence: the Court turned away AR-15 petitions for more than a decade, including Friedman v. Highland Park in 2015 and Snope v. Brown in 2025, and the Viramontes petition itself sat through 22 conferences before it was granted on June 30, 2026.

Start from the Court's reversal rate. The Court reverses or vacates roughly 70% of the cases it agrees to hear, so a neutral prior for the challengers is about 0.70. The post-Heller Second Amendment record (six gun-rights wins in seven merits cases) supports a higher prior, near 0.80.

Adjust down for the specific risk that the Court vacates and remands with a new test but no holding on AR-15s, which is how a Roberts-led majority could avoid a sweeping ruling. We put that at about 12 points. Adjust down again by about 2 points for a dismissal or a decision slipping past July 3, 2027. Adjust up by about 8 points for the four justices already on record and the United States switching sides. That gives 0.80 minus 0.14 plus 0.08, or 0.74.

The Kalshi market on the same question last traded at 82 cents, with a 74 to 83 cent spread, but it runs until 2030 and counts any ruling that recognizes the right. Our tighter July 2027 window and stricter definition explain most of the gap.