I disagree. The Supreme Court is constantly having to decide what the Constitution actually says about things. In many cases it's a matter of interpretations because the wording of the Constitution is ambiguous or doesn't fit the questions we are faced today- such as matters dealing with computers, mass media or the internet- things that were unimaginable in 1776. And these interpretations are just that- just the opinion of whoever is on the court at the time and subject to change at anytime.
In the case where the Constitution talks about the right to bare arms- it is in a amendment talking about "A well regulated Militia"- many people think that means that ONLY those in a government organized militia have the right to have guns. The wording of this amendment is so ambiguous no one can say for sure- so people interrupt it however they want it to be.