I'll be using 150 gr Partitions in a .270 for elk.

Are you going to be reloading or using factory rounds?  I killed quite a few elk with a .30-06 and 165 grain bullets and a couple with 150 grain one.  For reloading for the .270 I think that I would go with the barnes 140 grain TSX BT or the 150 grain MRX BT.  Load data can be found on the Barnes web site.  Or for a Nosler bullet I would go with the 150 grain partition. 

For a factory round out of the 06 I think that I would go with the Federal Premium with the Barnes 165 grain TSX and for the .270 the 150 grain Nosler partition from Federal or the Federal 130 grain Barnes TSX. 

Here's some good info for the .270

http://www.ballisticstudies.com/Knowledge+Base/.270+Winchester.html

Hornady GMX  

.270    130 gr

30-06  168 gr or 180 

In my .270 I use 130 grain Speer Grand Slams and sometimes 150 grain Speer Hot-Cor bullets loaded atop IMR7828 powder.  Throws a 130 grain an average about 3080 ft/sec out of my rifle when chrono'd at altitude.  Throws the 150 grain about just a bit over 2900 ft/sec.

Used to use 150 grain Grand Slams and they worked well, however the BC of that bullet really kills the velocity and enegy at longer ranges.  Get much better enegry trasfere and BC with the 150 grain Hot-Cor Spritzer.

Overall though I've taken several elk with 130 grain bullets with no problem to hit the vitals.  Good luck finding these two Speer products anymore.  I just had a rude awakening last night when I found out they are being phased out and replaced by a newer bullet from Speer.

The thing about using any bullet for elk is to just make sure it's a relatively tougher constructed bullet design.  Doesn't have to be bonded or premium, just has to be tough enough to hold together to penetrate to the elks vitals.  Some bullets are made with softer lead cores and thinner copper jackets such as the Speer Boat-Tail bullets.  I would not use a soft high velocity bullet like that Speer Boattail on anything but pronghorn and smaller deer. It may just pancake under the hide on an elk or moose at close range and high velocity.  Just rule of thumb - the tougher the bullet the better for elk.  Keep that in mind and the .270 Win can handle just about any biggame throughout the world (except large borwn bears, polars, and rhinos, hippos).

130 grain accubond atop 55 grains of IMR 4350 = NIGHTS OUT

**obviously work up to max load