On substantive "pro-gun": I don't think it makes much of a difference in the House, because you have a pro-gun majority there regardless of which party the leadership comes from. Pelosi cannot get an anti-gun measure through the House.
The Senate is another story because of their "advise and consent" role on judicial nominees. What is going on in the third branch now is very important to guns.
But generally, when thinking about judicial nominees, I tend to look beyond substantive interpretation of 2A. On civil liberties, I am interested in a range of issues, many of which indirectly effect 2A rights.
For example, consider the 11th Amendment: under a activist, right-wing interpretation of the 11th Amend., embodied in Will v. Michigan State Police, if a State policeman -- or other state (as opposed to local) official -- falsely arrests you for open carry, you are without federal legal recourse.
I would very much like to see the Will case overturned: but the justices who voted with the Heller and McDonald majorities are also those who would vote to uphold the immunity for arbitrary and abusive state power in Will. They pull the same kind of crap on issue after issue in civil liberties cases, but many people who are concerned about gun rights exclusively do not recognize it.
Now that Heller and McDonald are settled law, I think that it is high time that gun rights people broaden their perspectives somewhat. That may mean -- contrary perhaps to the prevailing meme here -- that the "liberals" are the good guys.
Personally, I am uncomfortable with Senate activism in holding up orrejecting judicial nominations for reasons of judicial philosphy in most cases. The place to influence the judiciary is in presidential elections.
"liberals" or more accurately progressives will never be the good guys. What we do need is more libertarian officials.