If you go all the way with the 'right to bear arms', then everyone has a right to all sorts of weapons.
Landmines and rocketlaunchers for all!
In fact, in order to ensure we have a militia that can protect us from random shooters, we need mandatory concealed carry rocket launcher permits for people.
/logicalextremebasedonwording
I think the logical distinction in terms of self defense is that the typical firearm can be aimed, and against specific targets with minimal collateral damage under many circumstances. Explosives, and fully automatic weapons can not. So their restriction is allowable.
Many circumstances indeed. However, firefights by nature are typically chaotic, just look at friendly fire statistics.
As far as guns themselves, they are a tube which contains an explosive that propels a shaped piece of shrapnel in a single direction. Said direction is based upon who is aiming the device... which could be the average person, or someone whos even stupider than that.
A landmine on the other hand could be rigged to do a shaped detonation and only specifically against whoever triggered it, with a very specific placement on your property that you want to defend. With proper tech, you could even RFID chip people whom you don't want blown up. Etc etc, arguments arguments, blah blah blah.
The trick is, there are laws regarding arms even though if the 2nd amendment could not be approached at all, there would be none. We certainly don't want firearms in certain locations, and certainly make it illegal for prisoners to have them. Its not so much of holding the 2nd amendment up on a pedestal because we DO have limitations that chip away at it (both its wording and its interpretation). Limitations that sometimes people even agree on.
That said, there are places in this country where not having a gun (shotgun or rifle) can be detrimental to your health. We use said things for hunting, or defense against feral beasts (though sadly, usually for herpdederp I kin shoot sumtin). Would throwing dynamite into a lake be good for fishing? Well.... people have done it, and it sorta does work, but its dangerous, stupid, and harmful. For such things, we typically would want to do the necessary gear only and not overkill, and overkill is specifically the problem here: things which are designed more for killing large amounts of people rather than use as tools and self defense.
Note: remember, SWAT teams need the AP bullets due to
http://www.angelfire.com/super/killmurderhog/caligunmen.html (sorry about the source).