My go to bullet in the .257 Roberts had been the 100 grain Hornady Interlock but I don't know that they are available any longer. Might have to try a BT now.
In my experience the "improved" Ballistic Tips tend to retain about as much weight as Interlocks, about 40% to 60% of their original weight, and work very similarly on game.
Of course, these days many hunters--even deer hunters--think bullets need to retain at least 90% or they won't kill well. This has not been my experience, even on larger game. One of the African PHs I've hunted with more than once mentioned during a discussion that he thinks 40-60% weight retention is just about perfect for all but the largest game. His favorite all-around load for culling, or backing up plains-game hunters on any game smaller than eland, is the 130-grain Interlock Spire Point in his .270 Winchester....
