If gun shops and manufacturers are responsible for what happens after the sale then:

Car manufacturers are responsible for accidents and DUIs

Alcohol manufacturers are responsible for DUIs and alcoholism

Tobacco companies are responsible for cancers of the mouth and throat

Candy manufacturers are responsible for diabetes and obesity

Electric companies are responsible for electrocution

Baseball teams are responsible for fans getting hit by balls and bats*

Rope manufacturers are responsible for hangings/lynchings

Razor companies are responsible for cuts

I could go on and on and on. But once again, notice how they never want to blame the FBI for any of this. Colorado guy passed an FBI background check for his gun when he shouldn't have cause he was on the FBI watch list and I believe, every mass shooter in the last 8 years, has been known to the FBI. Always wanting to blame someone or something else, instead of the lunatics who commit these crimes.

I'm starting to think the FBI is behind all of these mass shootings as a way to implement gun control.

*Back of tickets for baseball games specifically say they are not liable for balls or bats hit, or thrown into the stands