I would suggest work up your loads, then check how the sights align with range.
I thought perhaps a 1910 might have sights in yards, but with loading so early in it's life I feel no judgment can be made.
I've thought the 270gr. was the bullet the sights were likely set for.
Perhaps the 9.5x57 lacks the zeroing trait that .375H&H and my .375/06IMP enjoy, where the different bullet weights strike together.
Depending on how you are holding the rifle on the rest, the 235's might shoot lower when you get closer to it's preferred loads.