I've had my PC .460 for 5 years and it's accuracy still amazes me. If you don't reload, I suggest you stick to .44 magnum unless you have really deep pockets. When one reloads you can have custom ammo for not much more than .44mag. If you must buy factory ammo, hunting type ammo is pretty pricey....somewhere between $2-$3 a round. It's hard to enjoy the gun when it's breaks the bank everytime you go to the range. The 200gr Hornady ammo is accurate and is only about $1.50 a round, but my experience is it's too fragile for deer sized and larger game. You also MUST wear ear protection EVERY time you shoot it. EVERY time.
As far as shooting other calibers outta it. If you reload, you don't need to shoot other calibers, you just load down your .460 brass. Other calibers will print quite differently than .460 loads and you will continuously be adjusting your sights. Shorter cartridges tend to leave a crud ring which raises pressure quickly and makes for hard extraction if you don't get it all out when going back to .460 loads.