I rebarrelled a Wincester Model 88 to 338 Federal a couple of years ago, and went with a 20" barrel. Built this rifle specifically for bear hunting and bear watch work. Using the Federal Premium 210 NP ammo exclusively. Has a rear ghost ring site on a rail and a Trijicon front sight for low light work. Currently has a Leupold VX-3 1.75-6 scope in qd rings mounted on it. Took a nice caribou with it last month. Haven't had much time for bear hunting of late.
Chose 20" as that is also what my Browning BLR in 358 Win has, and I really like how it handles. It has been my main back-up guiding/archery/atv/horseback rifle for 15 years and has accounted for lots of game, from deer, moose, elk, black bear and grizzly bear.
As a lefty, I really like the levers, and like detachable magazines too.