Whatkind of range are you getting out of your 257 bob or IA
About 3 miles?
Heres the data for my 115g Barnes TSX load @ 2958fps, zeroed for Maximum Point Blank Range for a 6 diameter target (bullet is never more than 3 above/below line of sight):
000 yards = -1.5, 2958fps, 2234fpe
100 yards = +2.6, 2747fps, 1927fpe
250 yards = +0.0, 2449fps, 1531fpe
295 yards = -3.3, 2372fps, 1437fpe
360 yards = -10.2, 2242fps, 1284fpe
400 yards = -15.9, 2170fps, 1202fpe
Thats from a .257 Roberts with +P loads.