There's nothing the 140 can't do that the something in 120 will do, might be a hair flatter showing for awhile but that would be overcome by the 140 quickly...I 'be shot a railroad car full of deer with 140 partition out of a 7 mm mag at 3100 fps, none ever survived to take a couple of steps if that...best hunting bullet ever made !
Here is JBM. I "sighted" them in so the bullet never went above 3". I sighted the 120 in for 290 yards and the 140 in at 260 yards. I don't have a 7 Mag, but if I did I would go with the 120.
120 BT @ 3,500
0 -1.8 *** 0.0 *** 3508.0 3.142 3278.5 0.000 0.0 ***
50 0.6 1.1 0.1 0.3 3388.4 3.035 3058.8 0.044 7.7 14.6
100 2.1 2.0 0.5 0.5 3270.1 2.929 2848.9 0.089 15.6 14.9
150 2.8 1.8 1.2 0.8 3153.3 2.824 2649.0 0.135 23.8 15.2
200 2.7 1.3 2.2 1.1 3038.1 2.721 2459.0 0.184 32.3 15.4
250 1.6 0.6 3.6 1.4 2924.7 2.620 2278.9 0.234 41.2 15.7
300 -0.5 -0.2 5.2 1.7 2813.3 2.520 2108.6 0.286 50.4 16.0
350 -3.7 -1.0 7.3 2.0 2704.0 2.422 1947.9 0.341 60.0 16.4
400 -8.1 -1.9 9.7 2.3 2597.0 2.326 1796.7 0.397 69.9 16.7
450 -13.8-2.9 12.6 2.7 2492.3 2.232 1654.8 0.456 80.3 17.0
500 -20.8-4.0 15.9 3.0 2389.9 2.141 1521.6 0.518 91.1 17.4
140 Partition @3,100
0 -1.8 *** 0.0 *** 3106.8 2.783 3000.1 0.000 0.0 ***
50 0.8 1.5 0.1 0.3 3005.3 2.692 2807.2 0.049 8.6 16.5
100 2.3 2.2 0.6 0.6 2906.1 2.603 2624.9 0.100 17.6 16.8
150 2.8 1.8 1.3 0.8 2809.2 2.516 2452.7 0.152 26.8 17.1
200 2.3 1.1 2.4 1.1 2714.3 2.431 2289.9 0.207 36.4 17.4
250 0.5 0.2 3.8 1.4 2621.5 2.348 2136.0 0.263 46.3 17.7
300 -2.5 -0.8 5.5 1.8 2530.6 2.267 1990.4 0.321 56.5 18.0
350 -6.9 -1.9 7.7 2.1 2441.5 2.187 1852.7 0.381 67.1 18.3
400 -12.7-3.0 10.2 2.4 2354.2 2.109 1722.6 0.444 78.2 18.7
450 -20.1-4.3 13.1 2.8 2268.7 2.032 1599.7 0.509 89.6 19.0
500 -29.2-5.6 16.5 3.1 2184.9 1.957 1483.7 0.576 101.4 19.4