as afr as generaly available bullets goes yes the 280 will have higher BC bullets available than the 25-06. Wildcat bullets makes some heavier longer better BC bullets gor the 25 cals that may be woth a try , not to sure what you'lll be able to stabilize in a 1-10 twist.
The 162gr A-max is an awsome bullet for the 280 , they are relitivly cheap and have a pretty high BC , their not to hard to load with like the VLD bergers can be in some guns , the best thing about the Encore is that you can seat your bullets out as far as you want with not having to worry about magazine length issues.
What barrels do you have for your Encore? 24" , 26" , heavy? any work done to it? The encore can be made into a fine shooting rifle capible of making shot out to the same ranges as the bolt guns , you just gotts know what they like
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