In short, he is shot.
While that sort of thing will annoy the gun loon crowd who want people to believe that walking around with weapons is somehow "normal" in a civilised nation (or is the message that the people in the US are savages or barbarians?), Archie will die saving the first openly gay character in the series, Kevin Keller.
"The way in which Archie dies is everything that you would expect of Archie," Archie Comics publisher and co-CEO Jon Goldwater said in a statement. "He dies heroically. He dies selflessly. He dies in the manner that epitomizes not only the best of Riverdale, but the best of all of us. It's what Archie has come to represent over the past almost 75 years."
"We wanted to do something that was impactful that would really resonate with the world and bring home just how important Archie is to everyone," Goldwater continues. "That's how we came up with the storyline of saving Kevin. He could have saved Betty. He could have saved Veronica. We get that, but metaphorically, by saving Kevin, a new Riverdale is born."
Well, I am sure this will definitely make an impact on the reality challenged right wing. I'm sure we can expect the usual bullshit from them.