I have shot whitetails with the 243, and it really didn't impress me much.Great for the gophers and yotes though. I don't have any hands on experience with the 7 mm, but have lots of friends that use, or have used them. Also have a bud that sold his 7 mm mag for a 25 06, which he uses for moose, elk and whatever else that he is after. He totally lost faith in the 7mm after a bullet failure on an elk. I turned him on to the 25 06, and he has never looked back. Given the right circumstances, a 22 rimfire will kill a deer or moose, but with better options available, wouldn't be the tool of choice.