Have you looked at Tester's voting record? He as voted pretty much down the democratic line, opposed trump at nearly every turn. He is pro-illegal immigration, support sanctuary cities, Opposed trumps SCOTUS pic etc. I don't see a 2A vote as a US senator, but my guess is he would follow the Democratic line when the time comes. The problem with these "conservative" democrates is that they talk a conservative game, but they vote with the party on nearly very vote especially the cloture vote which is often much more than the final vote.
