The Supreme Court in DC. v Heller [1] determined:
"The Second Amendment protects an individual right to possess a firearm unconnected with service in a militia, and to use that arm for traditionally lawful purposes, such as self-defense within the home"
The definition of the militia in federal law [2] is not limited to those with membership in a formal organization:
"The militia of the United States consists of all able-bodied males at least 17 years of age..."
> We aren't allowed to have indentured servitude, but we legally have the draft in times of crisis.
In my opinion Arver v US was a war-time sham case and the 13th amendment's prohibition of "involuntary servitude" clearly and unambiguously prohibits the draft.
> We have the freedom to speak and share our world views, but I cannot yell "fire" in the movie theater
This quote is from Schenck v United States and was written to support the Supreme Court's decision that criticizing the draft was illegal and not protected by the first amendment. Fortunately this was later overturned.
> How does a suppressed destructive device on an unregulated currency exchange make our society better?
Suppressors have a legitimate purpose in reducing hearing damage to the user by taking the volume of a firearm down from jet engine to lawnmower. As for the 51 caliber, I can only assume the previous poster simply thinks that applying a federal "tax" to barrels over 50 caliber is arbitrary and capricious.
> How did you come to believe you needed this capability?
The police not only have no responsibility to protect anyone, but also no responsibility to even actually show up when you call. We saw in the recent Florida shooting that multiple officers on the scene are perfectly willing to hide and completely ignore the murder of children. On this basis (among others) I see no reason for civilians who are not police officers to have legal access to anything less than what is available to civilians are are police officers. If there were firearm restrictions that applied to everyone I would be intrigued, but I have yet to see any legislation that does not completely exempt police (they are exempt even in absurd cases, e.g. from state laws restricting firearm ownership by people with a history of domestic violence).
[1] http://www.scotusblog.com/wp-content/uploads/2008/06/07-290.... [2] https://www.law.cornell.edu/uscode/text/10/246