No the federal Government can not regulate the possession of a machine-gun because that is purely a local matter. Joe use the machine gun for his own and never took any part in interstate commerce. According to Wickard v. Filburn Congress can regulate purely intrastate activity that is not itself “commercial,” in that is is not for sale but its for own use.
1.Is it a defense that Joe’s possession of the machine-gun was insignificant in the grand scheme of things? After all, he is just one person who possesses only one firearm.
Yes Joe allow defend his possession of the machine gun that was not significant in the grand scheme of things, because he did not use or carry the gun during a relation to the crime. In the Gonzales v Raich case the law in california is to use marihuana in medical purpose but not to effect on interstate commerce. Therefore Joe did not use the gun to effect on interstate commerce also he did not fire the gun while FBI agent was in the bar.
1.Will Joe be convicted for owning a machine-gun based upon Gonzales v. Raich?
No Joe will be not convicted for owning a machine-gun because the gun was “home-made” and never traveled in interstate commerce. Based on Gonzales v. Rich case Congress power to regulate purely local activities that are part of economic that have a substantial effect on interstate commerce. According to the law congress can not regulate the possession because Joe use the gun for his own not on effect interstate commerce.