I am not sure where you read that the U.S. Supreme Court upheld any state laws regarding certain types of firearms as being "outside the boundaries of the 2nd Amendment." I personally believe that the term "Arms" in the 2nd Amendment encompasses only firearms, but that ALL firearms are protected and that most gun laws are an infringement. I do have to disagree with this statement however,
"for the purposes of preserving the common welfare and the protection of our police and military against weapons more powerful and designed for the sole purpose of killing human beings without just cause."
The 2nd Amendment has nothing whatsoever to do with the protection of the police and military. In fact, it was explicitly meant be a counterbalance to a "standing army." If anything, the writings of the founders bear out that they believed an armed militia was necessary because of the threat that a standing army may someday come into power. The Amendment's purpose was never to protect the police and military, who are armed agents of the State, but rather to protect ordinary citizens from those very armed agents should they become the armed thugs of a tyrant. Our founders came to this nation with a radical idea never before tried by any European government. Their radical idea was of course to trust and grant power to individual citizens not the government. Now I see liberals not only trusting the government, but expecting government assistance (intrustion) into all areas of life. These same liberals who don't trust their fellow citizens to carry guns, and who clearly mistrust the Bush Administration inexplicably believe that the very government they claim to mistrust should be the only ones armed.
You talk of automatic and / or semi-automatic weapons being outside the boundaries of the 2nd Amendment. If the intent of the founders was to draft the 2nd Amendment as a protection against tyranny (as is undoubtedly the case) then couldn't one logically conclude that it would be necessary for citizens to own military equivalent arms that are in common usage? What good would the right to bear arms be if those arms were so outdated as to be ineffective against the government? I can't image that the founders intended for the citizenry to own arms far inferior to those held by the government. If that were the case then the 2nd Amendment would have no "teeth" and would be rendered useless for defending against tyranny.
Surely you understand that "semi-automatic weapons" are protected by the 2nd Amendment. On what logical grounds should they not be protected? They fire a round with each pull of the trigger. Furthermore, legally owned fully automatic weapons have only ever been used in ONE documented crime, and that was committed by a police officer with access to such weapons.
In my opinion the type of firearm a citizen may own is irrelevant. As a law-abiding U.S. citizen I should be allowed to own a fully automatic weapon, a semi-auto AK47 or AR15, a semi-auto shotgun, pump shotgun, semi-auto handgun, or antique musket, flintlock etc. The government should not place an a priori restriction on what type of firearm I may own because of the presumption that I may commit an illegal act with it. Instead government should punish those who actually commit violent crimes. We don't govern all cars to 65 mph under the assumption that the moment someone gets behind the wheel they are going to break the speed limit. We don't ban high powered "assault" sports cars for "public safety" or claim that the average citizen "non-professional driver" doesn't have the training or maturity needed to operate said vehicle. Unfortunately I see this exact kind of arrogance when people discuss firearms.
Furthermore, the purpose of firearms that you state is also irrelevant. The fact remains that firearms deaths account for very few deaths in this country. They are not designed "Solely to kill" anymore than a kitchen knife is designed to kill. They are used in a predatory means by violent criminals, and in a protective means by the thousands of law-abiding gun owners in this country. More children are killed by drowning in swimming pools than are killed by someone with a gun, yet pools are not designed with the purpose of killing children. Heart disease is the #1 killer in this country yet the government doesn't restrict peoples choice of what they can eat. Automobile accidents kill more than firearms each year, yet we don't try to ban them, and any idiot with half a brain can get a license to propel thousands of pounds of metal at speeds high enough to easily kill a person. Hell, mothers against drunk driving doesn't try to place innumerable restrictions on adults who like to drink. They don't blame the alcohol, or the car, they blame the person and his choice. It should be the same for firearms. Punish the actor for his actions, not the object.
I'm going to cut this short with one last thought that is somewhat crude. Anti-gun people assume that I might kill someone at anytime and that I am a threat if I simply carry a gun in public. They're unable to even consider the advantages of owning and carrying a gun. Do I have the means to take a life or commit a crime if I'm carrying a gun? yes, but I also have the means to protect lives. By the anti's logic I'd also be a constant threat because I possess the equipment between my legs with which to commit rape, and women everywhere are prostitutes simply because they have a vagina.
I could say much more on this topic, but I think this is good for now.