I am going to need time to consider this but it really does seem that this will come down to how Gambit has dealt with some of the big-name sharpshooters in the Marvel Universe (e.g. Domino, Bullseye).
It would also be key to see what kind of range Gambit has been able to produce with his abilities.
To just make an earlier estimate, Deadshot seems to have range and skill here. But, I provide what I think may be relevant but I am unsure if it counts as pre-New 52 since I am pretty sure it is out of continuity but regardless there is no reason this should work.
I'll put the image below but I'll quote it since I needed to take the photo and the quality may not translate well.
Batman to Deadshot: "Bite-activated locking mechanism. Interesting. Secondary armor beneath the kevlar faceplate. Clever. The blood liner is a stroke of genius, but not nearly as innovative as the insulated costume that masks pulmonary functions and breathing. All designed so you can play possum if you're shot" - Batman: Cacophony, Kevin Smith
I'll leave this here and follow along before I vote but I will say I am leaning Deadshot on this one.