I would stay with the 150 gr also. The heavier bullets will expand slower, if at all, and in my opinion, transmit less energy into a light skinned animal like whitetail deer. The lighter bullet will expand and slow down faster, thus putting more energy into the deer, translating into knockdown power. I actually prefer the bullet to stay inside the animal, that way I know every bit of energy carried by that bullet was absorbed by the deer. Just my personal preference, yours may be different. Hope this helps. Good luck.