Given this assessment, and without using a (verbose) structure of "I support RKBA, but [opposing viewpoint] and [discussion & exposition] and therefore [reasons why we're doing it wrong]" I would be interested in seeing, as two completely separate (brief) statements of 1) what you personally believe is the scope and nature of the right to keep and bear arms -- not expressed as the views of a third party, and 2) what is the best approach to persuading those who would infringe upon this right to cease such infringement and instead support one of the original civil rights.
K.
1.) The "existential ends" (scope and nature) of the RKBA are basically twofold; to provide for yourself (hunting) and to protect yourself and those around you (personal defense). I understand the presence of entertainment value, but the Founders did not give you the fundamental right to plink, or for that matter to collect. It is, though undoubtedly very positive, only a side effect of the RKBA which has the main purpose of providing for the common defense, and by so doing promoting the general welfare.
Therefore, you have the right, and I fully support that right, to own whatever gun you feel is necessary to accomplish those ends. If that is no gun because you rely on a monitored alarm and the police a block away, fine. If you feel you need military-derived rifles in strategic places around your home, fine. I however have the right by free speech to question the circumstances by which you feel you need those arms to the degree you have them for said existential ends, and why you chose arms in lieu of other devices that would also ensure security or provide for yourself.
Quite simply, you have the right to own arms, and I have the right to challenge your need based on my stated purpose of the RKBA to own your particular choice of arms. You can, in kind, challenge my stated purpose of the RKBA or accept it and defend your need under it; both are valid rebuttals and reasoned discourse can proceed from there. However, to do neither does not rebut the challenge, and in debate, if you cannot refute a challenge your position is weakened. If you can't explain WHY you need the gun, or explain WHY my interpretation of the RKBA is wrong, all you're doing is Constitution-thumping, arguing by repetition that you are right. I hear a lot of that on these boards, and it DOES NOT WORK.
2.) Complex question; let me first state what it is NOT; The best approach to persuade those who are against guns is likely not going to be made on a general level or in the general case. It is not going to be to "firmly stand your ground". I've used the analogy of a brick wall; a brick wall looks strong and impenetrable, but no wall is immovable and no wall is indestructible. Even one built to deflect damage from one angle is vulnerable from another angle.
A better defense, though counterintuitive, is analagous to a wall that is firm but yielding; it absorbs and redirects force directed against it, and returns to its original shape and place. A bowling ball of sufficient speed will smash through a brick wall with significant damage to both; a mattress will absorb and redirect that force, and remain largely unaffected as will the bowling ball.
How is this applied to arguments levied against guns? Concede, then refute and redirect, and by so doing you regain your original position and possibly even gain ground while the argument focuses elsewhere. Any one of these three, if done by itself, is damaging. Conceding alone is simply giving up ground. Refuting presents an assailable solid wall, and redirection makes you look like you want to ignore the issues. When someone shoots up a mall or school with an AK clone, immediately saying "Guns don't kill people" accomplishes exactly nothing. It presents a solid wall of verifiable, unassailable fact that any emotional argument to the contrary will tear apart in the eyes of the public. Immediately blaming the kid and only the kid, who is beyond retribution, accomplishes exactly nothing; it does not appease those who are rightly enraged at the act and does not contribute any possible solution; how are you going to prevent this from happening in future? Each kid who does it has paid the ultimate price before the DoJ got their hands on him, and justice after the fact is the only recourse of a truly free society. The nation's discussions on this topic are not a moderated debate where the rules of logical argument apply and are enforced. A fallacious argument sounds perfectly reasonable, and to refute it your argument must not only sound reasonable but must sound MORE reasonable than the fallacious one, and pointing out the fallacies is only part of it.
You first have to concede the logical point that a high-powered semi-automatic rifle is a very powerful, very deadly weapon and its use by those who are ignorant or uncaring of the consequences has obviously tragic consequences. To concede that fact does not harm your position; to ignore, discount or refute it on the other hand is damaging to your credibility and the strength of your argument. THEN, you state your argument that the gun itself is not the problem. You are still going to meet resistance; you must, although they are both logical fallacies, appeal to the masses and to emotion, because the Brady Bunch is highly adept at doing same. A logically unassailable argument ("a gun with nobody at the trigger will never kill anyone"), made with what is perceived to be an uncaring tone will, in the public forum, simply be ignored in favor of one that appeases the anger and hurt felt by the public. That's the position the Brady Bunch has you; they coddle and appease, and thus appear to be "in tune" with the public, as opposed to the gun lobby, who bleats the party line and, it often seems, refuses to acknowledge public sentiment that people have been murdered by a man with a gun, and the public doesn't want it to happen again. Any such acknowledgement usually comes across as a one-sentence or one-clause preface to an argument that then begins with "but".
How do you appeal to emotion and the masses? Redirect. It's the kid's fault, and the kid, if he hadn't offed himself, should have been responsible for the consequences, but a kid driven to do something this horrific is NOT in his right mind, would NOT have done it under different circumstances, and DID NOT decide to do this all of a sudden on the morning of the shootings. THAT's where you direct focus; why did he do this, and how was he not noticed and stopped before he did? Yes, that's going to give him more media attention, but to ignore the killer is to ignore the real problem. It's dismissive simply to call him insane (we aren't all criminally insane; something drove him to it), and naive to think that fame is all that drives people like him. It is also dismissive to say that the particular gun he had did not in some way contribute to the fear and therefore the damage, however intangible, he was able to cause. This was an act of terrorism, and it succeeded admirably; people want to be safe, and will entertain any and all options that appear to ensure it. You therefore have to give them that.
Longer than I wanted it to be, but the main points (I hope) are obvious so Arfin can skim it without getting the wrong idea. I support RKBA, and I oppose restrictions that prevent me the gun owner from buying, keeping and using the firearms I feel are necessary to protect myself and, if it were necessary in my case, to hunt for my food. The weapons I feel are necessary are less... "controversial" than the weapons at issue here ("assault weapons"), and frankly if assault weapons went away the only effect to me personally is that handguns would become the front line, a line I will defend ferociously. For others here military-design rifles are a line that, if crossed, DOES affect them personally, and if you give me a logical argument that will appeal to the masses I will throw whatever weight I have behind it. I can defend my choices; that should be the only test for me and indeed for anyone to own X firearm, but "because I can" is NOT a valid reason for owning a firearm of any kind, and the Second Amendment, by its stated text, did NOT have that intention. You MUST have a better argument than that, that makes the Second Amendment applicable in the eyes of the public the same as it was 200 years ago, and not just BECAUSE it was applicable 200 years ago, that defends your right to X firearm, or indeed to X number of firearms. That will be difficult, but it must be done.