Accuracy will not or should not be effected by a 20" barrel if any optics are used. Little shorter sight radius with open sights depend on your eyes and it is made for quicker close in work. You would be giveing up a little in velocity. You can buy the Afican model and get the 23" barrel if lenght is an issue and you feel longer shoots are the norm.
Ruger designed this with hornady so why not call ruger and talk to them about velocity difference between the 20" and 23" barrels . Probably no more than 100fps.
I don't think a bear at 50 yards or less would know the difference when a 300gr bullet hit it.