Not to throw a curve at you but: I think of myself as a pretty decent Elk hunter. Two years ago I switched from centerfire rifles to ML's. I am hunting with either a Remington M700ml or or an Austin & Halleck, both 50 cal both 26" barrels.
The load I have chosen to shoot for elk is a Nosler .458 (45/70) 300 grain Protected Point Partition bullet in a .458 Orange MMP HPH sabot. I feel good about this bullet because I know the capabilities of a Nosler Partition, I have been reloading them for years. Another reason the .458 is a rifle bullet not a pistol bullet. The velocities that I am shooting at over my chrono is only slightly below 45/70 specs with a 100 grains of t7. The accuracy is outstanding. I just wished they got there faster, but that is one of the things I give up going to the ML.
For recreational shooting, target shooting, I shoot a Hornady .458 - 300 grain hollow point bullet.
To be truthful with you, the SST is a fine bullet; the plastic (polymere) tip is an asset for those type bullets. I have used a simular Nosler bullet with the plastic tip in my 270 for deer hunting. The tip really helps start and control expansion of the bullet of course it does help the BC of that bullet a lot. And in the same breath I would tell you the XTP-HP Mag is a proven bullet and has performed well for a lot of people.
Good luck and good hunting