Massachusetts' contribution to firearms rights case law, the infamous Caetano stun gun case, was cited by the Federal district court in Barnett v. Raoul. The judge issued a preliminary injunction against enforcement of the recently-passed Protect Illinois Communities Act (PICA), which bans "assault weapons" and standard-capacity magazines.
“Next, Judge McGlynn found what is undeniable – that AR-15s are in common use and thus meet the Heller-Bruen test for protected arms: ‘more than 24 million AR-15 style rifles are currently owned nationwide,' and they accounted for ‘nearly half of the rifles produced in 2018, and nearly 20% of all firearms of any type sold in 2020." "Under the Caetano test, even 1% of the 24 million AR-15 style rifles held by citizens is sufficient to result in a finding that such arms are in common use.'"
As Volokh notes, “To make the statistics vivid, consider that sales of AR-15s more than double the sales of Ford F-150 pickup trucks.”