Are you pretty familiar with your gun? I sugest spending a few hours at the range, trying different positions and ranges. Standing, sitting, kneeling, standing with a rest, etc.
Just try to imagine there is a basketball in the deers ribcage between his front legs, slightly further towards the rear, and try to shoot there. That is the easiest kill area (maybe not the quickest, but easiest to hit.) and try to take out one of the legs with the shot too, either on the way in, or the way out. Don't worry about the caliber either, you've got plenty of punch. I expect to see a picture of whatever you get up here soon