So, it comes down to "Should Congress be regulating machine guns or shouldn't they"?
No, because it interferes with the ability of the militia to show up in possession of military weapons of the type in common use in our times.
The
Miller decision said the sawed off shotgun was not protected because it was not "ordinary military equipment, or that its use could contribute to the common defense." Well, a machine gun IS ordinary military equipment, and its use can contribute to the common defense.
Miller went on to say: "The signification attributed to the term Militia appears from the debates in the Convention, the history and legislation of Colonies and States, and the writings of approved commentators. These show plainly enough that
the Militia comprised all males physically capable of acting in concert for the common defense."
And further said: "when called for service these men were expected to appear bearing arms supplied by themselves and of the kind in common use at the time."
Congress is clearly preventing the establishment of an effective militia by preventing "all males physically capable of acting in concert for the common defense" from appearing for service "bearing arms supplied by themselves and of the kind in common use at the time."
Shall we also get into the whole thing about privately owned warships again? ;-)
"These show plainly enough that the Militia comprised all males physically capable of acting in concert for the common defense." Be careful with the language. Note that it does NOT say, "All males physically capable of acting in concert for the common defense comprise the Militia." Big difference.
Secondly, the Militia has been redefined over the years by Acts of Congress -- the Militia Act of 1792, the Militia Act of 1862 (actually an amendment to the Militia Act of 1792), the Militia Act of 1903 -- the latter establishing the National Guard.
Essentially, the Militia referred to in the second amendment no longer exists. The second amendment, therefore, must be read as to its intent -- the federal government shall not infringe the ability of the states to arm themselves for their protection and the protection of the nation.
The Spanish-American War of 1898 demonstrated weaknesses in the militia, and it was determined that the best way to accomplish this protection was the formation of the National Guard. That is today's "Militia", if you will.