RE: 300 WSM for deer or any hunting?
If you can get a good deal on one and have aspirations of Elk hunting in the future, then go for it. It is a good caliber. It may be a little more than you "need" for deer, but who cares. I shot a nice doe with my .300 win mag last year with 165 fail safe and she dropped 10 feet from impact. It did wreck an entire shoulder though. Good luck.