It's not the 3 grains I'd worry about, but the relatively light construction of the Interlock. I used to load those in my wife's Bob, but decided after seeing one come apart on an oryx that they're just not tough enough for game larger and heavier than deer. For big, heavy-boned bull elk, I'd like to have a more robust bullet to ensure good penetration. You want a bullet that will stay together and get through thick hide, solid muscle, and heavy bone to the vitals to do the important work. Ideally, you want an exit wound to facilitate blood loss and help create a good blood trail to speed recovery. Based on my experience, Interlocks are not what you need. The Partition, or other 115 to 120 grain premium bullet, is more likely to provide the performance needed to (more) reliably reach the vitals of a big bull elk and put him down.