Brother owns a couple of them in .257. They are 3/4" five shot guns with hand loads. I used one of them in Michigan on a deer hunting trip. Took three different loads with me, and all worked very well. My favorite was a 100 grain Nosler BT at 3000fps. Dropped a 313lb. buck like it was a rock. Plus I tagged eight or ten coyotes with it later that night (actually two different nights). The other loads were heavier. One used a Sierra 117 grain bullet and the other might have been a Nosler 115 grain bullet. The scope was a 2.5x-8x Leupold with Leupold rings and bases.
I went with eight other guys to Michigan, and everyone of them used a 30-06. They all laughed at me with the pipsqueak rifle. 300lb. deer were common up there, and they all told me to plan on doing a lot of tracking. The following year six of them had .257 Roberts rifles.
gary