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 Honest question: Do you think with all the weapons of this kind sold since then, will there be a significant reduction with just a ban or will we need to retire the weapons already out there?