When the constitution was written, most Americans lived on the frontier surrounded by hostile British soldiers, French trappers and Indians. The right to bear arms meant the right to join a militia like the one at Lexington and Concord.
Times have changed. While we still have many Native Americans, they are no longer warlike. I haven’t seen a British redcoat except in movies, and Frenchmen no longer come to trap in our forests. If they did, they most likely would not bring guns with them.
Certainly the founding fathers here in America did not mean that citizens should carry concealed guns on the streets of big cities or into classrooms and churches.
The frontiersmen in 1787 when the Constitution was written didn’t have automatic rifles. They didn’t even have six shooters.
Do do not confuse the framers of the Constitution with Wyatt Earp and Doc Holiday. The framers weren’t wearing gun belts. Sure Thomas Jefferson, Alexander Hamilton and George Washington went to war and they probably went hunting too. They didn’t carry guns into their offices, or meeting rooms.