If you peen that rivet just a little they tighten up very fast. Put the pliers on a flat solid surface, like on top of a bench vise, so the rivet is solidly supported, and whack the rivet with a small ball peen hammer, not too hard, dead center as possible. There's probably a better way to do it, like a punch with a rounded tip, I don't know. Don't hit too hard, you can make them so tight they're useless very easy, and I don't know any way to undo that. It's like a haircut, if you don't take enough off it's easy to fix, make it too short, that's hard to fix.