to be fair you must compare loads using bullets with similar sectional densities to get an idea downrange
7mm Rem Mag 140 gr. Ballistic Tip @ 3300 fps
+/- 3" Point Blank Range of 326 yards (277 yard zero)
100y - 3100 fps, 2985 ft-lbs, +2.4"
200y - 2910 fps, 2630 ft-lbs, +2.6"
300y - 2725 fps, 2305 ft-lbs, -1.3"
400y - 2550 fps, 2020 ft-lbs, -9.9"
500y - 2380 fps, 1760 ft-lbs, -23.8"
-----------
300 Win Mag 165 gr. Ballistic Tip @ 3200 fps
+/- 3" Point Blank Range of 318 yards (270 yard zero)
100y - 3000fps, 3300 ft-lbs, +2.4"
200y - 2810 fps, 2890 ft-lbs, +2.5"
300y - 2625 fps, 2525 ft-lbs, -1.8"
400y - 2450 fps, 2200 ft-lbs, -11.2"
500y - 2280 fps, 1910 ft-lbs, -26.4"
&
7mm Rem Mag 175 gr. Partition @ 2900 fps
+/- 3" Point Blank Range of 291 yards (246 yard zero)
100y - 2730 fps, 2895 ft-lbs, +2.6"
200y - 2565 fps, 2550 ft-lbs, +2.0"
300y - 2405 fps, 2250 ft-lbs, -3.9"
400y - 2250 fps, 1975 ft-lbs, -15.8"
500y - 2105 fps, 1725 ft-lbs, -34.5"
--------
300 Win Mag 200 gr. Partition @ 2900 fps
+/- 3" Point Blank Range of 289 yards (245 yard zero)
100y - 2715 fps, 3275 ft-lbs, +2.6"
200y - 2540 fps, 2860 ft-lbs, +2.0"
300y - 2370 fps, 2490 ft-lbs, -4.0"
400y - 2205 fps, 2160 ft-lbs, -16.3"
500y - 2050 fps, 1865 ft-lbs, -35.6"
I dont consider two inches at over a quarter mile to be 'flatter shooting', not in the real world. The bigger impact energy of the 300 makes up for the difference.