Don't forget bullet construction...150 gr bullets in a .270, in general are made for larger game than whitetail...How much internal damage a bullet does to an animal (assuming both hit the same area, or one doesn't hit bone and one does)...Is dependent on bullet construction (hard vs soft) and velocity of the bullet when it hits the animal, the faster a bullet hits an animal the faster it upsets and it will leave a wider wound channel...

All this being said, a 130 grain .270 bullet vs a 150 gr .270 bullet, with both bullets shot from the same distance, the 130gr will do more destruction and usually put the deer down quicker....You are not only using a higher velocity bullet, you are using a bullet constructed for deer, not elk...Now, if you hunt in an area that might have elk, moose, bear or something larger than deer, you might want to use a 150gr .270 bullet (or a 180 vs 150 .30 caliber bullet)....But lighter bullets will shoot flatter and create a larger wound than a comparitable heavier bullet....

Many hunters think just because you use a heavier bullet you are putting more energy into an animal, when this just isn't the case...If you leave a smaller wound and the bullet exits the animal, you don't know how much energy is actually being dumped into the animal....