It scares the heck out of me (and pisses me off) how many gun owners have no idea what they are doing. Never taught by dad/grandpa, no hunters ed, no gun handling ed, no LEO/military experience, no skilled buddy spending significant time with them. When I go to a public range I usually spend the first hour helping folks how to put a bullet on target, how NOT to point a loaded gun at others on the range, how to zero a scope, how to hold a rifle, how to hold a handgun, how to load a magazine, how to unload a fixed magazine, how to open a revolver wheel, which bullets/shells to use with which firearms (really scary), etc etc etc at which point I realize I will never get any of my own stuff done with any comfort I will not get shot by one of this people and I leave.
We need at least the following regulation: Any person in the US may only own or possess a firearm under five conditions (1) they can demonstrate basic weapons operation/safety based upon significant past experience; (2) the successfully complete an in person firearms operation and safety course; (3) have served (and been honorably discharged) from the armed services or law enforcement agency where firearms training was part of the job; (4) they are in the immediate presence and control of someone who meets one of the first 3 for the purpose of developing sufficient skills to meet #1; or (5) be a declared active member of a well regulated citizen militia that has formed to defend themselves from the government. Absolutely constitutional - even for those who are armed to revolt against the king.