I've killed several deer with the Sierra GameKing, and a couple specifically with the 165 BTHP GK. All were DRT.
This is a premo bullet, plain and simple. The HP is a little "harder" than the SP, with only a tiny loss of ballistic coefficient to the SP. That said, you needn't worry about tip deformation with the HP.
I had loved this bullet so much, that when I began reloading for my .300 Win Mag years back, I thought I would use that same bullet. Oops. When pushing it in excess of 3000 fps, it gets a little flimsier, said Sierra. (I was hunting elk.) No problem with elk, or even bear or moose with it out of the '06, but out of a Magnum, I needed to move up to the heavier 180 grain bullet. I did. Because I also had an iron-sighted '06, I started loading 180s in my .30-06 (the slightly more arc'd trajectory didn't bother me under 200 yards).
The 165 is a nice compromise weight, and is close enough to match weight (168g) that you can pretty much just load to the same velocity interchangebly.
I was reared up believing that there was no powder for the .30-'06 with the 165g bullet but 4064. In the early '90's or so, my father tried 4350, and we found that his Ruger M77 shot it better, so we shifted loads. In the late '90's, when we started playing with magnums, we had some RL19 lying around, and found it works, too. IMHO, the 4350 is pretty much the way to go, though.