I struggle with guns because they are so complicated. I believe in personal freedom but you can't just have everything. At the same time, I don't think it's the government's right to know everything you have. That's big brother.
I think I would define the "right to bear arms" as handguns, shotguns and rifles. Any gun of that caliber, you are free to own and privately trade without any registration. To me, right to bear arms really should be "right to personal defense" and should be the idea that you are allowed to own guns to protect yourself and your family.
It seems like the big debate in the past 20+ years as been the AR-15. Technically, the AR-15 i just a rifle. It's scary to people because it looks big and scary and has a high capacity cartridge. The argument is why do you need an AR-15? Why do you need a PS5? Why do you need your nails done? Why do you need a car that goes over the speed limit? etc. etc. It's a bad argument. That said, you can do a lot of damage with AR-15s and if we find that they are being used in more than 50% of mass shootings, you unfortunately do probably need to regulate that.
So perhaps you regulate ownership of guns that hold high capacity carts. Maybe you *do* register those type of guns. Maybe for those type of guns or higher caliber guns, you have to get a license and certification.
The big issue for me is that the genie is out of the bottle. Even if you banned all guns, guns still exist. We are not the world. They are still being made, the patents exists and they'll be made in other countries. People that want guns will get guns. If you became really strict and put people away for 10 years for gun possession, people will simply turn to knives and other weapons. You'll fix mass shootings but now you'll have a knife epidemic on your hands.
The reality is the people that own guns are not the people doing these mass shootings. It's mentally ill people getting their hands on guns. The better idea is trying to find ways on how to made it harder for those type of people to get guns.