Disclaimer: I am not a lawyer, just a random layperson posting on THR
This is my take on the significance of Bruen ruling in terms of historic SHIFT in how the Supreme Court will address future 2A cases after receiving final merits decisions from lower courts.
Prior to Bruen, interest balancing "greater good of society/community over individual right" was considered for 2A cases.
Bruen changed that and did a historic SHIFT refocus on individual rights protected under the Second Amendment factoring previous Heller/Caetano rulings to expand 2A protection to include "modern" arms and accessories (As ruled in
Cargill bump stock case).
So now "Text, history and tradition" must be used for Bruen test with burden shifting to the state/government. Notice, consideration for interest balancing "greater good of society/community over individual right" WENT OUT THE WINDOW.
Bruen methodology was reaffirmed in Rahimi as chief justice Roberts explained -
https://www.thehighroad.org/index.p...-nysrpa-v-bruen-decision.913941/post-12928828
In Bruen, we explained that when a firearm regulation is challenged under the Second Amendment, the Government must show that the restriction “is consistent with the Nation’s historical tradition of firearm regulation.”
"Government must show that the restriction 'is consistent with the Nation’s historical tradition of firearm regulation' ... Government ... bears the burden to 'justify its regulation'"
In Bruen, we directed courts to examine our “historical tradition of firearm regulation” to help delineate the contours of the right. We explained that if a challenged regulation fits within that tradition, it is lawful under the Second Amendment. We also clarified that when the Government regulates arms-bearing conduct, as when the Government regulates other constitutional rights, it bears the burden to “justify its regulation.”
But since Bruen ruling, some lower courts CONTINUED to use interest balancing "greater good of society/community over individual right" argument, which BTW was tossed out by Bruen, in support of mass shooting based consideration for ruling against "modern" arms and accessories ruled in Heller/Caetano/Cargill.
And when historical analogue to ban "modern" arms and accessories could not be found, some lower courts expanded regulation examples of Bowie knives. And when that argument didn't work, started using "military use/military grade" argument to ban "modern" arms and accessories because such increased "lethality" over non-military arms. In
3rd Circuit ruling for Gray v Jennings, court made the argument that "military grade" .223/5.56 AR15 must be banned because higher 3000 fps muzzle velocity was double that of 1600 fps 9mm pistol (Wow, when 9mm Major is around 1400-1450 fps

... Where did they get that ammunition?) and increased "lethality". Well, does that mean bolt action rifles must also be banned if they produce greater than 3000 fps muzzle velocity? And BTW, 9mm pistol is also used for "military use/military grade" so it must be banned as well?
In response to non-compliance by lower courts, chief justice Roberts stated,
... some courts have misunderstood the methodology of our recent Second Amendment cases ... As we explained in Heller, for example, the reach of the Second Amendment is not limited only to those arms that were in existence at the founding. Rather, it “extends, prima facie, to ALL instruments that constitute bearable arms, even those that were not [yet] in existence.” ... Holding otherwise would be as mistaken as applying the protections of the right only to muskets and sabers.
As increasing number of lower court rulings pointed out, while mass shootings are tragic, Bruen methodology focuses on individual right to use arms, including "modern" arms and accessories for lawful purposes, including self-defense. And if state/government cannot produce historic tradition evidence of analogous ban, then "modern" arms and accessories cannot be banned, no matter how much hand waving is done for interest balancing "greater good of society/community" as Bruen ruling separated that from Bruen methodology.
Even the 9th Circuit recently ruled applying Bruen methodology -
https://www.thehighroad.org/index.p...apply-to-future-2a-cases.931586/post-12988679
At Bruen’s second step, we conclude that the Government has failed to prove ... categorical prohibition ... “is part of the historical tradition" ... The Government put forward no “well-established and representative historical analogue”
IMO, I believe that is what the Supreme Court will clarify and reaffirm in future 2A cases.