Mike - Back when I did my big game hunting (mostly mule deer, elk and bear) with my Contender's I only used pistol length barrels, factory at first and then custom wildcats, and that too was in the wide open spaces of the west where shots could be long. Any of those same cartridges would work fine in a carbine length barrel. Which factory barrels would work is a no brainer, but there is quite a few possible (IMO better) choices for the Contender if you'd consider custom wildcat barrels. Just pick a caliber you like and there will be at least a couple or more possibilities for that caliber, and many of them are very easy to form brass for. Picking a favorite myself would be hard since so many work so well, and it would depend on if it was only for deer or a one barrel that does it all for big game. For deer only I have at least several wildcat favorites in 24, 25, 26, 27, 28 and 30 calibers. For the do it all, the 375JDJ always got the nod.