Can someone tell me where in the 2nd amendment it says you can carry machine guns?

[NuclearEnergy]

I have come across these video on YouTube of these so called "second amendment" acitivists carrying their AR-15's into public places like a Walmart, Starbucks or any other sort of private business. They seem more in the business of getting reactions from people. I just do not understand why they do this? Sure, the legal BAC is less than .08 but that does not mean it would be OK for me to be driving with a BAC of .0799999999999 

Also, there has been studies that the entire good guy with a gun thing is a huge myth. They found the majority of the time this good guy with the gun will either freeze, or get mistaken by as the perpetrator by the police.

I have zero problem with owning guns. But there is such a thing as taking something too far, and this is it. 


Also, one other thing. I would like to see someone who is middle eastern looking do this same exact thing. I guarantee you these open carry idiots would be calling them a terrorist. 

https://www.youtube.com/watch?v=naTSklJmB2o

https://www.youtube.com/watch?v=rzw8jW0aCys