Nate45,You are absolutely right.I have never loaded 120 or 130 gr bullets in my 7 mag.I also have no doubt they are perfectly adequate for antelope.Actually,I do not take my 7mm antelope hunting anymore.I use 115 gr Ballistic Tips in a .257 Ackley.I cannot think of a better combination.
I think there is more than one way to do things.Your way can be right,and so can mine.
Small shades of grey,a 160 Sierra Boat tail will be less affected by wind if a 400 yd shot happens.But,for me,even that is minor as I try to be closer and closer yet in the wind.
What does matter to me(you can do it differently) is my rifle is a different rifle when I change ammo.If I practice,sight in,and know my trajectory within my duplex withe a 120 gr bullet for antelope late September,then I'd have to load 140's if I went deer hunting.different bullets,load development,etc,learn the holdovers.Oh gosh,I drew a cow tag and I can buy an over the counter bull,so now I'm using 175 partitions another trip to the range,but I have only shot the sight in rounds before I go to hunt.Or,worse,badweather,schedule conflict,I cannot get out and re-sight in.
For me,not for anyone else,for me,I like 115's in my 257,180's in a 30-06,165's in a 308,140s in a 7-08,69's or 75's in a 223,depending on which one,260 accubonds in my .375.
That is what I load,practice with,and they are always zero'd with.
While,once again,I agree the 120 will work great for you,a 160 will also work great for me.Cheers!!!