When I was a kid, in SE Texas, everyone I knew used the 150gr, in any make. It was felt the 170 was too tough and killed slower than the 150. Granted, these were small deer and everyone shot hogs behind the ear, so no matter.
Every Marlin 336 I ever had ( 3) shot the 170's better ( and the Speer 170 hotcor is awesome in a 30-30 Ackley Improved I gave a friend) I even loaded up some Hawk 190 soft nose in a standard 30-30 at 170 speeds. never killed anything with them, but they shot swell. Only problem I ever had with the 30-30 was one year I tried (in a Mod 94, when I was a teen) the Winchester 150 Hollow Point. It didn't open up well, but I got my deer by breaking it down, neck shot finisher.
That speer 170 HotCor is one tough bullet, from what I saw what it did to a 300+ pound hog my friend shot, it would work swell on elk. It may be too tough on deer w/o a shoulder shot. Good luck to you!