Lots of good advice here. Lots of good questions for you to answer before you decide what to buy. Going to a match or two and seeing what others are shooting is a great idea, but when one wants to shoot, one wants to SHOOT and not merely watch, so all of us get that.
Assuming the rifle is for target or even competition (as opposed to hunting) use:
Do you reload? Are you an experienced reloader or do you have a friend who is and who can show you the finer points? If no, then stick with something for which good quality ammo is readily available, if there is such a thing as readily available ammo these days.
Understand that, assuming again that you are not a very experienced competitive shooter, that you are on the steep part of the learning curve and probably don't really have any idea what many of your preferences are. Perhaps you don't really even know if you'll like this enough to keep doing it for years. Perhaps you don't have an unlimited budget like some here seem to. Consider these things before you crap a lot of money on the latest go-to gear.
I am an experienced reloader and had some competition experience from two decades ago (highpower). I found a second-hand but new custom barreled action in .300WSM (26" SS Krieger, trued action), bought a second hand AICS for it, a 16X SWFA Super Sniper, a 20MOA mount, and a Harris bipod, bought some Winchester brass, dies, and went off to shoot 800, 900, and 1000 with ammo I had loaded. Ballistics programs work surprisingly well and getting on paper was not an issue.
I sold some other stuff and bought a used 700 SPS Police in .308, added a moderately priced scope, base, etc, intending to use it for practice, and did so. The factory chamber was so long that it would not let me seat VLD bullets long enough to reach the lands. I shot SMKs (which don't mind jumping) for practice, working out position, follow through, etc. SMKs in .308 are not competitive at long range, so serious competition use of this rifle was not an option.
After about a year and a half, now convinced I'd be doing this as long as I could still see, and on the advice of some friends who were experienced F Class and Palma shooters I moved into .308 for competition. I took this practice rifle and had it rebarreled, trued the action, mounted it in a new AICS, mounted a new Sightron, etc. It is now my primary match rifle and I shoot FT/R, Berger 185's, etc.
The point is that you can reuse what you already have and grow into the sport.
Did I mention I'm broke?
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