If I wanted to hunt with a Contender , whats the biggest caliber I can hunt , Thanks in advance

Not sure I understand your question, but if I am interpreting it right, I believe the TC Contender ML barrels are .45 caliber. I think the Encores go to .50. There might be larger bore. Contender ML barrels after market, not sure.

We're not allowed to hunt game with them in Oregon. There's no allowance for ML handgun regardless of bore diameter, not single shot, not revolver. To cheat the rule, I tried some .433" round balls in .44 mag cases over a case full (38? grains) of 3F in a 12" TC .44 mag barrel. It didn't work out, probably too much velocity, as the groups were roughly a foot in diameter at 25 yards. Might be able to improve the situation with more wad (so there is no air space) and less powder. Not sure I'll bother.