If RKBA is not covered by the 2nd, it is indisputable that it's a natural, inherent, inalienable/

unalienable right covered by the 9th Amendment as I've discussed on DU many times since 2001.

Following are some of my posts that IMO answer your question particularly the second one:

http://journals.democraticunderground.com/jody/36

http://journals.democraticunderground.com/jody/1

http://journals.democraticunderground.com/jody/42

http://journals.democraticunderground.com/jody/37

http://journals.democraticunderground.com/jody/35