I have loaded some 120s in a 7 mag. Unless you just want them to blow up coyotes at 300 yards or less, you are better off with a 140-grainer. The 120s are speedy at first, but the 140 or better will win if you are looking at long range.
My bil shot a deer with some 120 Hornadys out of a 7 mag. At 310 yards, they dynamited. They killed the deer just fine, but I was not impressed. A 139-grain Hornady or other brand will serve you better in my opinion.
That weight may be OK if you are looking to use the Barnes or like bullet.