Which is kind of odd, because the definition of "machine gun" is a federal one and that is not what the federal gov't says a MG is.
"Jurisdictions can define things in their laws as they see fit, they are not bound to use the same definitions as other jurisdictions (superior or inferior)."
"DC has had 'home rule' of the non-federal portions of the city for many years now (mid 70s).
Congress can exercise a veto of ANY home rule action but rarely (if ever) does."
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There's a reason that
Heller was brought in DC, aside from the outright ban: DC is a creature of the Congress. Because ANY DC law can be vetoed by Congress, then any laws on the books there are assumed to be approved by Congress.
WRT full autos, Congress AND President Roosevelt II (Traitor, NY) passed the NFA. That's more than mere Congressional approval, that's US law. As such, even Congress cannot override it. DC is as bound by the definitions in the NFA (or any other part of federal law, for that matter, even those not in any way related to firearms) as the Congress itself is bound.
Put it another way: I'm Jewish. If I define a pig to be the same as a cow, because both have 4 legs and are born live, is it OK for me to have a ham sandwich (assuming that I want to obey the Law as put forth by the ultimate Lawmaker)? The correct answer is "No," because my authority as an individual does not extend to changing the definition of a cow...just as DC's authority (via Congress) does not extend to changing the definition of "machine gun" as specified in the NFA.
Were DC a state, we might have a bit more trouble (until the 2nd is incorporated via the 14th, which is in the works with the suits against SF & Chicago).