Re: New here! Got some questions!
Let me first start by saying welcome aboard!
Any of your sugestions will do the job.
The 300 WBY is a great round and w/a good bbl it can work miricles.
The 300 WSM is also a great 1k performer and can be very accurate.
The 308 might be a little weak at 1k on deer, but w/the right bbl, bullets and shot placement, the 308 can work that far. This would be your most inherently accurate case vs the 300 WBY or WSM. However, the others will offer less wind drift and more punch when you do connect.
Anybody who knows me knows I am a 308 finatic. They are cheap enough to operate and easy on barrels, you can afford to go out and get "married" to it and be VERY lethal, even between 600-1000 yards on medium game. They dont kick hard, have less muzzle blast and are very accurate. Savage also makes a 10FP tactical rig w/a 26" tube in a McMillan A2 stock for around 800 bucks!
Long range shooting is a process that ends with a result. Once you start to focus on the result (where the shot goes, how big the group is, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.