There's a good reason 'the right to keep and bear arms' was second only to 'freedom of speech and religion' when the founders framed the Bill of Rights. I mean, it sure wasn't the Fifth, Eight, or Tenth Amendment. It was not an afterthought. It was that important to the founders.
I Charlton Heston once said if we didn’t have the 2nd amendment we wouldn’t have the first.
I hate to disappoint you, but what is now known as the “second” amendment was originally the third or forth, (don’t remember for sure).
The proposed bill rights had twelve amendments. They were in no particular order.