Small point of order. Gun ownership is not a constitutional right. A right granted by man can be taken away by man. The constitution is written legal evidence of the premise that we are guaranteed certain rights by our creator ie:God. “Among those Life Liberty and the pursuit of Happiness”
That why the progs have have not eliminated the 2A yet and it's not for lack of trying.
IIRC the Heller decision noted that the 2nd Amendment codifies a previously established right.
The First, Second, and Third Amendments prohibit the federal government (and due to the 14th Amendment, the states) from impinging upon these already existing rights.