I shoot 210 Bergers in my 300 Wby. Here are two 900 yard groups from last summers testing.
I just got back from the same range (pics are not ready yet) but the rifle shot even better this time. 2 groups at 1212 yards were 5in. and a little over 3in. This rifle will never get anything other than Berger 210's
I get 2988 fps with a turn neck chamber and 80.0 of 7828 (25.5 in barrel)