Further, men over 48 can still join the active militia, but are not subject to a militia call-up. Which again, in no way relates to "infringement" of their RKBA.
Presser v. Illinois. USSC, 1886:
"It is undoubtedly true that all citizens capable of bearing arms constitute the reserved military force or reserve militia of the United States as well as of the States, and, in view of this prerogative of the general government, as well as of its general powers, the States cannot, even laying the constitutional provision in question out of view, prohibit the people from keeping and bearing arms, so as to deprive the United States of their rightful resource for maintaining the public security, and disable the people from performing their duty to the general government."
The antis are eager to cite precedent whenever it suits their purpose, but they ignore it when it doesn't. IMHO in Presser the USSC set a pretty clear precedent for the 2nd Amendment's militia clause as a protector of the RKBA against violation by a state or local legislative body, but that precedent has been ignored by practically all 20th century federal courts. Although, if properly interpreted Miller doesn't contradict Presser at all. The court simply said that no evidence was presented to show that the firearm in Miller's possession had any utility as a militia weapon.