I don't buy into the fight against tyranny argument, nor the militia argument.
The 2a doesn't specify what purpose the arms will be used for. What it does specify is the "right of the people" and "shall not be infringed" leaves nothing to the imagination. It's pretty strong wording.
The constitution and the bill of rights was written to deal with future events. It was intended to span centuries. Without it, this country would have died long ago.