Lots of reasons the .257 Roberts igets so little love from the masses and the gun makers.
In no particular order:
1. .243 Win
2. The 7x57 parent cartridge is a mid-length cartridge. Although some makers use short actions for the Roberts, to take full advantage of the cartridge you need a mid or long action.
3. In a long action the .25-06 does everything a Roberts will do and then some.
4. Low SAAMI pressure when compared to other cartridges, even with SAAMI +P data.
5. It probably would have fared better if it was a .257 Remington or .257 Win. due to better marketing support.
My tang safety Ruger .257 Roberts is my avorite rifle by a wide margin. It loved the following loads:
75g V-Max
100g TTSX
110g AccuBond
120g A-Frame
My Ruger has a long throat and I seat the longer bullets out well past a length where they will fit in an M700 short-action magazine.
I had a 1982 700 Classic, which is a long-action 257 Rbts. It's not at all necessary for this cartridge, and in a long action and a 24" sporter contour barrel, the Classic model is a hog relative to the chambering. The Rbts really shines in a short-action rifle. 2.825" is plenty of length and with some powders will give the same velocity as a round loaded out to 3+". I'll concede most of your other points, but that doesn't make the Roberts inferior.
Browning BLR, Remington 760 pump, Remington 722 and 700, Winchester 70, Ruger 77 and Hawkeye, NULA, Kimber, etc. etc. etc. all can't be wrong.
Watch in the classifieds or search and see how fast a Kimber Montana in 257 Rbts sells. I have one and wouldn't take for mine. I loaded up some 75 Gr. VMAX's and my first 3-shot 100-yard group after 1 sighter went into .24" (or maybe it was .29"...don't care to look it up) and I stopped there and went and killed a ton of prairie dogs with it. I've yet to shoot a deer with it, but the 100 TSX is just waiting for the call.
