Hello there!
The Second Amendment automatically permits citizens of the United States to bear arms; however, this does not permit using any firearms or similar weapons in an inappropriate manner (such as withdrawing your weapon in a public area for no particular reason). Cases of this have been brought up in news articles and television shows various times. Generally, we can own any legal weapon that the United States Government permits, but can only carry it (concealed) in a public space if you have a license to do so.
I hope this helps!