Had several uneventful days driving roads in the mountains of Idaho looking for fresh deer sign in the snow, trying to get some ideas where to try and set up to hunt. Finally found a gated road nobody had walked in on yet as the fresh snow from several days prior was still untouched. Walked 1 mile in on the road and found a large clear cut. Sat for a while, rattled, grunted, doe bleated. After several hours I heard a buck grunt back one of the times. Unfortunately he came into the clear cut too far down for a pistol shot and quickly winded me in the swirling wind. I tried to shoot him with my '94 30-30 but the front sight covered up just enough that far that I didn't see a minute snowy rise in the flat light 20 feet in front of him and my shot skimmed a snow covered dirt patch and showered him with snow and dirt. He beat a hasty retreat into some steep nasty dark timber with blow-downs everywhere. I went and checked his trail from the shot to make sure there was no blood. Everything looked good, clean miss. Sat for a few minutes there and figured eh, what the hell, I'm already down here and sweaty. Tied some flagging to a tree and left my rifle leaned against the tree. Grabbed the GP100 out of my pack, and followed his tracks in the snow quietly for a couple hundred yards into the dark timbered blow-downs. All of a sudden I caught movement 10 or 15 yards in front of me and saw him moving through some thick trees but he didn't seem to be overly aware of me. Once he moved behind some thicker trees I made a clumsy tip-toe-sprint to get to the next opening. He caught my movement and kept going but seemed utterly confused by my spastic movements. I caught a good clear opening and fired at him at 20 yards quartering away, he stumbled and fell, got his feet under him and went over a small rise. I waited and listened... no crash, but no sound of his bolting into the depths of the dark timber either. After 30 seconds or so I crept forward where I could see a little farther, saw him struggling to keep his balance and navigate some downed logs, and quickly got the front sight settled and fired. Down he went! After several excited minutes I gathered my thoughts, looked back uphill with an anguished realization at just how far I'd gone straight down into the dark timber. I quickly got him gutted, cut in half, and arduously packed up to the road. Then began dragging him with the harness drag the 1 mile back to the gate where I had parked. Once back at camp I started my post-mortem exam. My first shot was about 1.5-2" higher than I anticipated (due to sighting it in zeroed for 100 yards, was about that high at 25 yards) and because of the angle the 158 grain XTP exited high on the other side so it only caught the top of the lungs, but the second shot, also quartering away, went in high behind the shoulder and the 158 gr XTP penetrated 18" or so and came to a rest in the neck after breaking a vertebrae but stopping. The recovered bullet weighed 141 grains and appears to be peeled back to roughly the cannelure. The 158 XTP was going 1500 fps at the muzzle out of my 6" GP100.