I like the 80-95gr bullets in a .243, I can't imagine a .257 roberts being any different on deer. I used a 25.06 one one mule deer doe, the Federal Premuim 117 Sierra, and it was great, bullet didn't blow up either. Shot her low in the brisket ( I was in a hurry and used the factory trigger, 6# or so,ha) at 80 yds. She ran downhill for about 60yds, layed down. I slipped up on her and at 50yds shot her in the head. I later had that rifle rechambered to .257 Weatherby. I'm nuts that way, ha. A 25.06 with a 26" barrel can be heated up very close to the .257W or slowed down to the Bob's velocity, lots of options for you.