At what point do you draw the line though? If your intent with the second amendment is to, as it says, stop a potentially tyrannical government, then do you also have the freedom to buy hand grenades? How about shoulder mounted surface to air missiles to stop those pesky government F-16s? Some drones with Hellfire rounds? An M1-Abrahams to drive down to the corner store in case an uprising should start when you are out getting the milk?
Are your neighbours free to mine the road outside your house in case insurgents should drive up some day? How about them buying some uranium and building a small detonator in their garage? Or perhaps brewing some toxic cocktail of poison gas in the local primary school science lab?
Any of the above can be classed as a weapon to deter others, never mind the unintended consequence of accidental (or deliberate) discharging of any of them killing multiple innocent people. If you cannot purchase any of the above at a local dealership, then are you really free, when your government can outgun you at any point in time?
I consider myself 'free' when I take steps to minimise the infinitesimally small probability that something bad might happen, and I know that the steps I take will not result in an even worse 'bad thing' happening.
I got rid of my guns when we had kids. The very very tiny chance that I would need to use a gun against an intruder was outweighed by the even larger chance that one of my kids may have found my rifles and thought of them as play toys. Or the even larger chance that someone could burgle our house when we were not there and take them. I was free to choose what I wanted to do, and I still do not feel any less protected or safe in my own home, or while walking down the street, or when sending my kids to school, or when visiting a bar or attending a concert... or doing pretty much anything that a 'free' American is actually dead scared to do in their own country today.