Just for grins, I looked up the .257 Roberts in my 1942 Outdoor Life Cyclopedia. While most of what is in this epic tome is complete balderdash, it does give you an idea of the zeitgeist of the time. Here's what it said:
". . . but for some reason the .257 [Roberts] has remained almost entirely a gun fan's rifle. Paradoxically, the majority of those who own this great all-round rifle have several others in the rack, and the men who need it haven't given it much consideration."
Jack O'Connor loved the round, and developed a bunch of loads for it. However, he lamented at some point around WWII that there was a lack of good bullets for it. Yes, they were out there, but they varied greatly in weight and this led to less accuracy. As we all know, Herr O'Connor became linked to the 270 Winchester and not the 257 Rob.
There was a period after WWII that saw a resurgence in interest in .257 Rob when folks brought back Japanese Arisakas and could not find ammo for them. They had the option of rechambering them for .257 Rob.
