These days Ballistic Tips are tougher than Core-Lokts. We have had great luck with the 100 and 115-grain BT's in the .257 Roberts for quite a while now.
The exception might be the round-nose Core-Lokts. Those retained the heavy shank-jacket after the PSP's did not--but I haven't bought any in quite a while, so dunno.
I really like the Ballistic Tip 115 grain bullet in the Roberts. It is very accurate in my rifle. I see no need to shoot bonded or Partition bullets for deer sized animals. It seems Nosler has toughened up the BT in the past few years. As I said I haven't shot he Core Loks I quite a few years and never in the Roberts, so I can't make a comparison. `I'll make a bold statement and say I really don't mind fragile bullets on deer with heart and lung shots. I used to shoot the 270, 130 Sierra when they had a thinner jacket. Sometimes they didn't penetrate fully and even came apart in the chest cavity. Deer shot with this bullet traveled about 3/8's of an inch.
