Handi and Ultra=Same thing. Pretty much, anyway. The Ultras have a little better polish and are a bit prettier in my opinion. Plus you get a nice Lamintated stock.
Both the Handi and Ultras use the harder receiver, and SB-2 receiver. These handle the higher pressures of centerfire calibers. You can easily send an SB-2 back to the factory to get fitted for any number of barrels...Centerfire, Shotgun(with the exception of the 10ga), and Muzzleloader barrels.
Hunting and Target work...then I reccomend the 25-06, 280, or 308 Bull Bull barrel. Or a 24" Bull Barrel 243, is nice too :wink: Thats just my reccomendations. Just depends on your needs. But these seem to be among the most accurate of the offerings.
These rifles can be as accurate as any, but may require a little tuning. So have that in mind. Some require a little more than others. Some shoot great out of the box.
Hope this helps a little.
-Aaron