I was stationed at Travis USAF Base about 20 years ago. My hunts were focused within Napa, Sonoma, and Colusa counties for coastal blacktails. I carried my Marlin in 44 MAG with 4X scope and it never failed me. Becuase of 100 yard maximum range, I often stalked and crawled to within good shooting range. This added much to the hunting excitement in my opinion. I suggest select a good hollow tip such as Hornady and wait until you can shoot directly into the chest organs from broadside angle. Your 45 will perform well.
Coastal bucks rarely exceed 130 lbs live weight. It doesn't take a big rifle to topple 'em but you'll have to watch your distance closely. I killed most of my bucks at approx 80 yards or so and my 44 MAG really shines at this range.
One year, my brother came out to hunt with me and brought his 30-30. The buck never knew what hit him.