ORIGINAL: T-bird
I've had a Win M70 .300WSM for 4 years now ... I've only used it on southern whitetails and have had my best accuracy with the 150gr Winchester Supreme Ballistic Tip. It shoots 'em right at an inch at 100yds and every deer I've ever shot with 'em has dropped like you hit it with a sledgehammer, at ranges from 15 yds to 350 yds. My best advice would be to try various loads and see what your rifle likes the best. Good luck!
I have to agree with T-bird. I have never had a deer take a step using 150 Supreme BT's. To answer your exit question, all mine have expanded andexited perfectly. Of course, when they hit the ground on impact, it really doesn't matter to me. I have been using 300 WSM for 4 years and killed 15 deer and hogs. For elk, the 180's would probably be better, but for whitetails, 180 seems overkill.
As a side note, I do not advocate Supreme ballistic tips in under 150 grs. My Dad lost a deer last season, and my brother almost did using 130 BT's in their 270's. They expanded too quickly and did not exit.