I have shot lots of deer using 125gr out of the '06, and all of them were pass thru's.
For deer, I would not go less than 150 gr nor more than 165 gr in the 30-06.
What's the difference between shooting 125gr's out of a 30-06, and 100gr's out of a .243
The 165 gr also offers better ballistics than the 150 gr.
How so?