KYODE
The 30-30AI should be a top chambering in a Contender. My brother has one, only in rifle length. I am very impressed with it. If I were to buy an additional factory barrel today to go with what I have, that would probably be it.
In a Contender a rimmed round works best.
I am with you, the load I am using in the 35 Bullberry is about all that I enjoy shooting recoil wise. It should kill about anything you would want to shoot, stone dead out to 200 or possibly 250 yards if you know the yardage to the target, and have a very steady rest.