I can't speak for the 6.5x55. But the open tip 139gr Scenars work great in my 260. Should be pretty close to the 6.5x55.
I use them for WT Deer and pigs. Most shots are between 75-200 yds. A high shoulder shot will drop them where they stand. A double lung shot just behind the shoulder makes a nice exit wound with a good blood trail. Most don't go much past 20-30 yds with that shot placement.
