"The .257 Roberts was hamstrung by limitations of 1934 bullets and powder. IMR 3031 was about the best they could do at the time."
Not to mention that quite a few "customs" were made from 1893 and 1895 Mauser actions which were considered too weak for proper loads. A .257 Robt. loaded to equal pressures of the .243/6MM Rem. will run right along side them and in some gun beat them. If I had the choice of hunting deer with any of the three mentioned, I'd take the .257. I just like it a little bit better.
Paul B.