What makes you think the National Guard isn't equipped with Ma Deuce, in several of her incarnations? They also have Mk-19 automatic 40 mm grenade launchers, M-1 Abrams tanks, Bradly fighting vehicles with 25mm chain guns F-15 and F-16 fighter jets,A-10 attack aircraft (with 30 mm Gatling cannon), and most "all the terrible implements of the soldier".
Not me, mind you, but some hold that individuals would be restricted to individual weapons. the ma deuce is a crew served weapon.
Now I look at the letters of marque and reprisal phrase, and that reminds me that ships of war were and are one of the very best kinds of crew served weapons. Such ships were private possessions, and were converted into privateers upon permission, need and cause. Before that they would have to be privately owned.
I am just saying that if your right as a gun owner arises from your status as an individual in the unorganized militia, then it could be reasonable to restrict those rights to individual weapons. That reading would not extend rights to individual weapons to adult women, because they are not considered members of the militia.
There is also an extension from age 45 to 65 if one has previously trained or served as an officer (or noncommissioned or warrant officer). That clause is referenced in section 311, but I don't remember it offhand.