Good luck with this crowd.
Input from the experiences in other countries, especially from those that clearly share cultural background and values, even if their constitutions might not be identical, would seem to be not only a good idea but necessary to learn from history. Those who quote (and frequently misinterpret) the US Constitution as though it was created with no influence from abroad are just showing their ignorance of history.
There is nothing in the 2nd amendment that prevents limits being placed on what specific arms may be carried by citizens or members of a well regulated militia. We have limits on fully automatic weapons that seem to be accepted by nearly all citizens, including those who sit on the Supreme Court, as reasonable. Limits on semi automatic weapons would also be constitutional. That is why the NRA fights so hard to prevent such laws from being passed.
Those who decry placing limits on second amendment rights by claiming that our freedom of speech or fourth amendment rights would then also be eroded have either simply never bothered to study the question or are disingenuous. We do limit first amendment rights as no one as the right to scream "FIRE" in a crowded theater for example, not even members of the NRA. There are similar limits, accepted by the Supreme Court, on many of our other rights guarantied in the Constitution and Bill of Rights.
Those who want unfettered access to any arm that a manufacturer is willing to sell try to draw a line in the sand in a political strategy that tries to link gun control to absurd political fantasies about UN armies marching in to the US or evil dictators controlling the US government. The fact that we haven't been invaded in two hundred years, the fact that our democracy has never been subjugated from within and the fact that the so called "well regulated militia" has not been activated, with the exception of the civil war, for over two hundred years to defend against either foreign invaders or dictators in the District of Columbia is somehow forgotten by those who claim that we are free only because of the second amendment. They trot out fantasy scenarios based on the Red Dawn movie to explain how their AR15s and hoards of dried food will defeat Predator drones, AC130 gunships, M1A1 tanks, the NSA, etc etc. Adolescent fantasies. The NRA recently claimed that the militia was called out in 1947 or something like that to remove a corrupt mayor in Tennessee. Laughable. Any armed insurrection in the USA would have what the US Navy liked to joke about the Russian Navy in event of war: it would have a short but exciting life.
With the exception of a very few anti gun extremists, virtually no one wants to ban all guns in the USA. There is strong support for hunting with guns in this country just as there in these "foreign" places with strong gun controls like Canada, Australia, Britain and Germany. Why even all those commie Ruskies enjoy a good hunting expedition. Self defense is also well supported. Neither self defense nor hunting however require AR15 type weapons. Hunters who cannot hit a target with less than half a dozen shots might well spend more time at the firing range than in the field. Serious hunters do not need AR15 weapons to bring down game. Davy Crocket sure didn't and neither did any hunter in this country prior to the time Armalite started selling to civilians. The AR15 may well be an efficient varmint rifle but is hardly crucial to control efforts. I don't see any reason not to use the Aussie approach of allowing special permits for farmers or others with better reason than Rambo fantasies to own such weapons. Even as a strong gun control advocate, I don't have any objection to sportsmen owning these rifles so long as the rifles are stored at the shooting club or other similarly secure and restricted setting. Nancy Lanza showed us that home storage, at least with whatever security arrangement she used, is certainly inadequate.
Would banning the currently virtually unrestricted sale of assault rifle based weapons just be the proverbial camel's nose under the tent? Possibly. Not as an opening to total bans on guns but perhaps to place similar limits on other high capacity, high rate of fire weapons. And those would not necessarily be bans but rather tightening access rules so someone cannot walk into a gun store and leave thirty to sixty minutes later with restricted weapons. It may not solve all problems but I rather like the ?Aussie rule that permit holders need community references in addition to a pulse in order to buy weapons. This is a complicated issue that involves balancing individual gun rights with public safety concerns. Rather than take the "line in the sand" approach advocated by the NRA, real gun enthusiasts would be better served by engaging in open give and take discussions about how best to modify gun laws to find an acceptable compromise. Extremist arguments from either side of the debate are not part of the solution.