There is so much controversy about the exact meaning of the Second Amendment. Many claim that this amendment authorizes every citizen to keep and bear arms; others claim that the amendment authorizes only a well-regulated militia.
Why not follow Switzerland's example. It requires all adult males from 19 to 34 to participate in the Swiss militia much like Britain's Home Guard of World War II? Of course, a compulsory militia would include women as well as men.
Then every adult would be schooled in proper weapons handling and would be required to present their National Guard or military reserve membership certification to purchase a weapon.