Those are perfect if you have a short action .257 Roberts. I don't, but I try to keep a small pile of .257 bullets on hand so I ordered some of these a while back. My M77 Roberts doesn't shoot anything great, but seems to shoot everything fairly well. I've tried everything from 60gr RN meant for the .25-20 up to 120's. One of the best shooting was a load for coyotes 75gr Hornady HP over IMR4064. Partitions all shoot just a little over an inch.
Have you tried the 90 grain Sierra HPBT Gamekings? This bullet has shot good groups in nearly every rifle that I've shoot them from. My Ruger 77s in 257 Roberts both have long throats and do better with bullet 110 grain and heavier. A friend had a #1 in 257 Roberts that had such a long throat that it wouldn't shoot anything to his standards, so he had it rechambered to 25-06 and groups were much improved.
