Quote:
246. Militia: composition and classes
(a) The militia of the United States consists of all able-bodied males at least 17 years of age and, except as provided in section 313 of title 32, under 45 years of age who are, or who have made a declaration of intention to become, citizens of the United States and of female citizens of the United States who are members of the National Guard.
(b) The classes of the militia are—
(1) the organized militia, which consists of the National Guard and the Naval Militia; and
(2) the unorganized militia, which consists of the members of the militia who are not members of the National Guard or the Naval Militia.
That is from the house.gov website and before you start in about 'see it means the National Guard', there was no National Guard when the constitution was written so it clearly could not apply to that and the National Guard would have no need for the 2nd amendment since their weapon are provided to them by the states. Ergo the only possible conclusion, per the Federal government which you seem to trust so implicitly is the unorganized militia, ie. every able bodied male 17-45 who is a citizen or desires to become one.