"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
We are missing the "well regulated" part of the second amendment. What we have is far from well regulated. Everyone should have to apply for a license for a firearm whether they buy from a private owner or from a store. There should be a federal registry of those that are approved to get a license and also a list of those on the "no buy" list. There needs to be federal minimum regulations (no assault weapons, silencers, bump stocks, etc.) If the problem is mental illness, as so many adamant second amendment supporters suggest (guns dont' kill people, people kill people), then there needs to be periodic mental evaluations of licensed gun owners.
Will it stop all mass murders? Of course not. But it is a start and is doing something. You would think that the law abiding gun owners would want regulations.
Also, when did the "militia" part of the second amendment get glossed over? Every Tom, Dick and Harry surely don't belong to a Militia.