I would not only reccomend but urge the use of a Partition in your situation. The BT, IMHO, is just not up to the task for elk, especially in a caliber like the .270. In most situations where you will find elk you may well be shooting through heavy timber or thick brushy areas where a BT may come apart (expand) in the twigs and ruff. In my experience the Partition powers through, and then on top of it gives you some serious bone boring capabilities if needed. I love Nosler BT's for flight performance, but with my experiences on deer, and even animals as small as coyotes, I've seen them fail on a shoulder of which an elk has a lot of. The differences between the bullets is as shown below. The Partition has just that to stop bullet expansion at a definite location. Partitions tend to retain a large percentage of their weight even when fully expanded. The BT bullet with the poly tip tends to expand immediately upon impact and mushroom to a greater diameter, especially at higher velocities or medium-close ranges. I hope that the water isn't too muddy now. :wink:
While the Partition would certainly be recommended over the Ballistic Tip for elk, and the heaviest bullet your rifle shoots accurately is good advice as well, there is certainly one more option to consider: the newer 140 gr AccuBond. From reports I have seen, it offers similar penetration to the Partition, yet shares the Ballistic Tips superior accuracy and ballistic coefficient. When I get my opportunity to take an elk I believe I will have my .270WSM loaded with Accubonds and Vihtavuori N-165.
Other good heavy bullet weight powders to try for the standard .270 Win start at H-4831 and IMR-4350 and continue through IMR-4831 and 7828, Reloder 19 and 22, Accurate 3100, 4350 and Magpro, and Hogdon 4350 and 1000. There are many others, but if your rifle doesn't shoot well with one (or more) of these powders, it probably won't shoot period.
Let my first post on this site be a ringing endorsement of partitions for that application. I have been experimenting with various bullets in my handloads. I have decided this year to load nothing but the Partition in my 30-06, 45-70 and 44 magnum. Still working on the 6mm. I have never achieved match grade accuracy with my partitions, but I get fine big game hunting accuracy.
There are two scenarios where you might shoot through an animal's hip:
an already wounded animal needs to be anchored before it can escape or move into inaccessible terrain
that is the only makeable shot you have (I am not referring to a broadside butt shot; I am referring to a raking rear shot).
The first is obvious and self-explanatory; the second is an option when shooting a large bore magnum with heavy bullets with high integrity, because penetrating from the hip to the vitals isn't all that tough.