I had my gunsmith do a cross hatch hone on my Max Chamber to help the brass cases grab the chamber walls a little better.
The 357 Magnum - Maximum shell cases have straight case walls as everyone knows, same as an Ackley Improved Rifle case. The Ackley Improved case design is supposed to grab the chamber walls, cutting down on back thrust on the bolt face allowing higher pressure loadings. I suspect that the straight wall pistol case will tend to do the same thing helping to cut down on back thrust on the Contender breach face.

I have not worked with my MGM barrel since having the hone work done. It is about time however.

Mo Long Tom depending on just how sloppy the TC Chamber is, you might be able to chamber 360 DW Cases with no chamber work. As was said above long seated, you can wind a 357 Magnum up to 357 Maximum Revolver velocity in a Contender with no trouble at all.
I would start working my loads up .5 grains at a time, and watch for pressure signs. I recommend using H110, LilGun, 300MP, or 1680 to work up loads. For bullets I would use the 180 XTP in the lower crimp groove, OR seated even longer. Not a real big deal in a single shot. You can also do the long seated loading using the 158 XTP-FP bullet.

Bob