I don't remember exactly what the deal is, but I seem to remember there being someone who wrote a long paper about it and the Cliff's notes version was that the 2A says "Keep and bare arms."
Bombs/grenades, etc... are artillery, not arms. Arms only applies to guns.
Therefore, to connect the two is actually not intellectually honest.
It was something to that effect. I'm sure someone here remembers the source on this.
And what is it about the defense against Tyranny that limits us to small arms?
I would always put things into the context of a militia member being called into action. He was expected to bring his rifle, and probably a base-supply of ammo, which would be the same as what a member of the standing army would have.
In today's context, it is a right to be able to have the same small arms, such as an M16 or M4, as a member of the standing army. The militia would not typically report for duty with a canon (or, I can only guess, some form of grenade) since he was not expected to be proficient with those items, as he would be a rifle or pistol.
I have a couple things to say on this:
1. M-16s and M4s come in 3-shot burst and full-auto. These are regulated by the same law that regulates our ability to own explosives (NFA 1934). By the same law, the M16 and M4 are lumped with explosives. This suggests to me that whoever is writing the laws and has chosen not to change them in over 80 years thinks that they are in a similar enough category to be banned together.
2. If you're talking about any organized group, they'll usually have some familiarity with explosives in some way, shape, or form. It could come from someone who has military experience, demolition experience, or even just an enthusiast. If you're talking about someone who has a weapon and can defend his town with it, then there can be no expectation of what his training level is.
This sounds like the same thing I see in movies and TV shows all the time. Someone has a gun, and everyone asks "why do you have a gun?" If the person isn't known to be a cop, then they always assume just because he has a gun, that he's either a criminal or there's something bad that happened to them (or they're a redneck and almost always end up shooting someone when they shouldn't).
The assumption most anti's have is that the average civilian isn't trained in gun use, and if they are then they are obviously mentally ill. You're making a similar assumption about explosives.
I'm not saying everyone needs to have grenade launchers. I'm saying you should have the option to without government interference.