My thoughts on this... Considering the purpose and context of the 2nd, it essentially protects a contemporary citizen-soldier's "kit". The stuff he/she needs to join up in common defense with their community, which includes survival gear, protective gear, and of course, a weapon.
Today's citizen-soldier would carry an AR-15 or variant. If there's one modern gun protected by the 2nd, that's the one.
Today's citizen-soldier would carry an AR-15 or variant. If there's one modern gun protected by the 2nd, that's the one.