A classic example of the 2nd amendment!
This action by an armed citizen was a by-product of the 2A. The 2A was added for the propose of allowing the citizenry to legally arm themselves so that the government fears the people and not vice versa. So that we the people can take things into out own hands if the federal govt. get tyrannical, which IMO it has already.
Self defense and hunting etc. come as a natural result of and function of an armed society.