I am a confirmed gun buff. I own about a dozen and will probably add to my collection as time goes by. I have been shooting, hunting with, and reading about guns for about 4 decades.
First of all, the idea of buying automatic weapons off the shelf at walmart is a bit of a stretch, since automatic weapons have been tightly controlled since 1935.
Also, every place in the USA that sells firearms is required to do a background check. You have to have a government issued photo id. If you have a felony record or have any one of several other issues, you do not get a gun. Its quite simple.
The states that have "shall issue" laws for concealed weapons permits have lower violent crime rates.
When Florida went to the "shall issue" law, the state law enforcement started a task force to track violent crimes committed by people with a CCW. The task force was disbanded after two years. Virtually no violent crimes were committed by holders of a CCW, except in self-defense.
More laws, in my opinion, won't do any good. Making law enforcement agencies share data better might. Having access to people being treated for mental illnesses might help.
But law-abiding citizens should be able to own a firearm.