I am not really an expert, but Matt Eastman is, and I have his book. The .257 Roberts (and .25-06) was made as a special order for one year only - 1968. Sorry, but he does not give production numbers, but there were not many. In the mid '70s, early '80s I had kids in college and I bought and sold lots of Brownings and Winchesters to supplement the income. I have had some "hard to find" items come through my hands. I have never seen a .257. Eastman believes that there were 100 or 150 units made for a distributor in that caliber. Found this info in the footnotes.

Eastman advises that there were 348 units sold in .284, a standard production item. BEWARE OF SALT WOOD. jack

"Do not blame Caesar, blame the people...who have...rejoiced in their loss of freedom....Blame the people who hail him when he speaks of the 'new, wonderful, good, society'...to mean ,..living fatly at the expense of the industrious." Cicero