168s (even out of a 26-inch barrel) are going to have issues around 875 yards where they go trans-sonic.
At our National Matches at Camp Perry my brother was doing great with a 1-10 twist Remington 700 until he got to the 900-yard line -- then the wheels fell of until we got him some 175s.
For whatever reason I was having trouble with the shorter distances. I'm sure it was me, but when I switched to the 168's things straightened themselves out and I clutched those rounds like a horny Asian hooker riding rodeo.
If I went out +457 meters, I doubt the 168's would be my choice.