"Funny, when I was a teen I used a bolt-action .30-40 Krag"
There's a video somewhere on YT of a man attempting a mass shooting - staged, obviously - using a weapon that was contemporary to the Second Amendment being written in 1789. He fires one shot, and by the time he's reloaded for a second everyone has run away. I can't find it, it being drowned out by reports on real mass shootings, but Business Insider ran an article on it that you can find Googling for "mass shooting 18th century gun".