The red line is when Republicans ended the national assault weapons ban.

Source:
https://www.channel4.com/news/factcheck/factcheck-does-gun-control-work
Also, https://www.instagram.com/p/CeEZJNJu5X2/
Note: In 2004 the Republican Congress refused to renew the assault weapons ban

FactCheck: does gun control work?

States with stricter gun laws have lower firearms deaths - but is one causing the other?

Channel 4 News

@AthenasOwl Do assault weapons account for the difference?

I don't really understand the assault weapons ban, or at least the way it was written – I could see banning firearms altogether, or banning certain calibers, but who cares if a mass shooter has a barrel shroud and a flash suppressor or not?

I know some mass shootings used "assault weapons", but it seems like the shooter would have murdered just as many people without them in most cases. Different features, not covered by the ban, seem more important: Bump stocks are now banned, for example.

So... I'm thinking something else changed in the last 15 years to account for more deadly mass shootings. Media coverage seems to be another common answer, but that doesn't seem convincing either.

@ech @AthenasOwl I found this informative. High velocity rounds appear far more likely to kill.

https://wapo.st/40GdG67

What does an AR-15 do to a human body? A visual examination of the deadly damage.

The Washington Post examined autopsy and postmortem reports from nearly a hundred victims of past mass shootings that involved an AR-15 style rifle.

The Washington Post
@royal yeah, rifles vs. pistols is a meaningful distinction: rifle rounds can have a lot more energy. And like I said caliber. But I don't think AR-15s are any more deadly if they have barrel shrouds, pistol grips, and flash suppressors on them.