“The lineal descendants of personal arms of the type in
predictable civilian usage are thus protected, but modern
weapons of the type that serve no ordinary civilian function are not.” pp44
I have to re-read pages 52 and 65, as I think we might be F%CKED.
I think it will be a very viable argument to point out that the prefatory clause refers to militia use, and that “common use” - being not in the wording of the entire amendment - is an inappropriate construct as “militia suitable” arms are not necessarily suitable for non-militia use, but the arms being protected are at minimum protected precisely because they ARE suitable for military use.
The footnote you mention covers Miller's classification of 'militia weapon' as being one in where members of the disorganized militia "were expected to appear bearing arms supplied by themselves and of the kind in common (military) use at the time". You know, how the Miller court looked at Miller's short-barreled shotgun.
The operative argument you're missing is:
"... In that respect, Miller may be in tension with itself. There is no justification to limit the Second Amendment’s protection to arms that have military utility."
But yes, Heller is making the case that backpack nuclear weapons are "of the type that serve no ordinary civilian function".