What Firearms Looked Like In 1791

In conversations surrounding gun control in the US, the Second Amendment to the Constitution is often brought up as proof that the Founding Fathers wanted US citizens to have the right to bear arms, but what kind of weapons were they talking about when they wrote it?

In 1791, when the Bill of Rights was added to the Constitution, there were no police stations; skirmishes with Native Americans were commonplace; and the colonists had just defeated the British Army in the Revolutionary War. 

Because of this, firearms were a huge part of everyday life - from hunting down dinner to forming one of the many citizen soldier militia groups that kept the peace in the newly formed country. Even dueling with pistols had its place in society. 

So what guns existed when the Second Amendment was written, and how has weapon technology and history changed the meaning of what constitutes "arms?" The guns from the past look and function much differently from the weapons of today, which would be unrecognizable to the folks who founded the United States.