Look at the Second Amendment (and what it doesn't say)

"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."

Take a look at what the Amendment does not say.

It does not say that the militia has the right to bear arms (which would be like saying that our army has the right to bear arms).

It does not say that people have the right to own guns to defend themselves or their homes. (It does imply that people have the right to own guns to take to a local militia call up to defend against the British or the Indians.) 

It does not say that guns should be regulated (which in those days meant "well trained"). It says local militias should be well trained. 

It does not say that people have the right to carry concealed weapons.

While the First Amendment grants the right of people to assemble, neither the First or Second Amendment states that people have the right to take weapons to churches, bars or school board meetings (or Donald Trump rallies, where for some reason guns and Bowie knives are forbidden). 

The First Amendment was adopted because the Founders thought a national army might become the fist of a tyrant. Instead of an army, they proposed militia, by which they meant local volunteers in a town, say, who would train together. (They weren't proposing our current National Guard, which is an army.)

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But that's ancient history. Our courts have, over the centuries, interpreted the Second Amendment in new ways, and that is settled law, I guess. Depending on which state you live in, you can own some guns but not others, defend your home, maybe secretly carry a gun when you go to church, etc. You can not drive around in an armed tank, but maybe you can carry a military assault rifle--or maybe not. We know this much. In the states with stricter gun laws, there are fewer gun deaths.

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