In this Encore adventure I have embarked on, I keep thinking about selling the Encore and buying a Contender. It seems a functioning 460 SW barrel is unattainable at less than $375, so I probably will go with 445 Super/Ultra mag. That is contender compatible. The other consideration for this switch barrel platform is Coyote. I was previously looking at 22-250, which is not safe in a contender, but I am open to other rounds. 223 is possible and a reasonable round, but I already own a 223 rifle and would really like something with a bit more zip. 223 AI is possible along with 204 Ruger. 223 AI doesn't seem worth it over a 223. 204 Ruger is pushing the low end for coyotes.
I can't get a 445 mag pistol or a 460 pistol any cheaper than I can add them to my Encore set-up, but I can get a NICE Savage rifle for the same price or less, so maybe I should just settle the switch barrel to the pistol rounds.
The contender frame and accessories are just a little bit cheaper, more available, and most importantly a little smaller/lighter which would be nice for a pistol hunting rig.
Anyways, MGM has a list of calibers. Any of these stand out as something better than the 223AI
http://www.matchgrademachine.com/chamberings_public.php