I'll admit that my initial response to this was back when I hadn't read the novels in a while, so I wasn't as familiar with Voldemort's tactics as I am now. That much is my bad.
Mind reading is something he does in combat, and like I said in that other thread which shall not be spoken of, the way Legilimency users make use of it is effectively pseudo-precognition. He'll know when Courier is about to shoot the moment the latter even thinks about shooting, and will take measures against that immediately.
Which, yeah. He has plenty of things he can do. He can teleport before dude can aim (he's used teleportation in combat before), transfigure his guns into snakes (tranfiguring an opponent's items is also something he did in combat), TK him off his feet, summon a massive column of Fiendfyre that will chase him down endlessly and prevent him from shooting, mind control him, fool him with an illusion, nonverbally pull up a shield made of silver to serve as a defense against the bullets before they're even fired...
After further consideration, I'm definitely picking Voldy in this fight. He takes this quite handily.