.243, 25-06, 30-30, and 30-06, 50 caliber sidelock, and with 12 gauge slugs. I would also like to comment on those who are shooting deer with 22 rimfires and one even stated a 12 gauge with 7 1/2 shot---WTH!!! If you are, please, please, please keep it to yourself!!!
I believe the original question of this thread was "What calibers have you shot (killed) deer with?" not "What calibers do you reccommend for deer hunting?" Montana hunting regulations state "There is no rifle or handgun caliber limitation for the taking of big game animals."
I live in rural Montana. A hill rises several hundred feet in back of my house. There are no neighbors within 1/2 mile to the West of my house or on my side of the hill or within 1/2 mile to the East of my house. 30+ years ago when I moved here, I cut my backyard 25 yds into the hill so I could shoot pistols off my back porch. I also put a steel plate on a tree 300 yds up the hill for a centerfire rifle target.
However, I now have non-shooting, non-hunting neighbors on each side of my house. The neighbor on the North side has two pet (???) cows, and the neighbor on the South has two horses. I often have deer in my yard. I recently put wire mesh pannels against my house to keep the deer from eating the tulips that are trying to grow there.
Several years ago I hunted most of the deer season (with my .257 Ackley) without seeing a buck that I wanted to tag. I like to eat venison. A couple of days before the end of that season, there were 4 does and 2 fawns in my back yard. So I quietly slipped around the house and put a .22 LR bullet behind one of the does eyes. I regularily practice with that .22 LR rifle shooting quarter size candy wafers at 25 yds, so the 20 yd shot on that doe was easy. The doe dropped dead in her tracks, there was no loud centerfire rifle report to upset the neighbors, and I had venison for the winter.
As to the deer shot with a 12 ga 7 1/2 load, you make the call.
I was hunting Hungarian Partridges in a wheat field ten or so miles from the nearest town, and 40 miles from a F&G office. It was also the second weekend of deer season. I was walking through the brush next to the field when a 2 pt Mulie buck jumped up in front of me, ran a few yards deeper into the brush, and fell down. As I walked closer to him I could see a fresh bullet wound on one of his rear legs that had broken the (femur) bone just above his knee. I doubt that I could have had a Warden come out there that afternoon to put that deer down, and I didn't want to walk away and let him suffer, so I shot him. Since I was bird hunting, I only had a 12 ga O/U shotgun with me. So I clicked the safety off the Full Choke barrel, slowly walked to within 10-15 feet of the fallen deer, and put a load of 7 1/2 shot into the center of his forehead. That ended my bird hunting for that day, and I tagged the buck and that ended my deer hunting for that year.
What would you have done?