Most of the complaints I've ever read about with the encore barrels have been with the 7mm's for some reason. You may be better off selling the barrel and starting over with a different caliber, just a thought.
I have about 10 different boxes of 30-06 ammo sitting on a shelf right now. They are different brands (Win, Rem, Fed), different weights (150, 165, 180), and different types of bullets (corelokts, power points, ballistic tips, whatever). When I buy a new gun I go through the factory ammo I have setting around to see what it likes. With my encore 30-06 it became obvious to me quickly that I needed to shoot 150gr bullets if I wanted to brag about shooting smaller groups.
More than anything else, I recommend getting a mixed bag of factory ammos and heading off to the range for a long day. I have two 30-06's myself, and have used this process for two other guys 30-06's. Someday I may buy another 30-06 and if I do, I'll already have the ammo sitting there on the safe. Then again I bought all that ammo at least 5 years ago and there's been a big difference in ammo prices since then.