To death. All standerd equipment. No morals all bloodlust. Takes place in an island. Provide reason.
I think it's pretty close but tam 2 wins due to Dredd's extra firepower. Also Deadshot has better range than Bullseye, and based on the OP's description of it taking place "on an island" I take that to mean they start at a distance.
On the other hand, honestly if they start completely apart and have to track and find each other, then Punisher especially has an edge on jungle etc. fighting/tracking. He could take out Dredd if he takes him by surprise. I'd also imagine Bullseye has a stealth edge on Deadshot. So it may depend somewhat on conditions.